Te mando Alguas fallas identificadas por modelo , tambien en estas paginaspodes buscar el circuito, te adelante que la segunda  las aclaraciones y lasnotas estan en rusohttp:\\WWW.highlandelectrix.fsnet.co.uk

http://www.rlocman.com.ru/en/index.htm

----- Original Message -----From: "Luis A. Arce" <luisarce3000@sinectis.com.ar>To: <electronicos-monitor@yahoogrupos.com.mx>Sent: Monday, February 25, 2002 7:18 PMSubject: [E-monitor] AOC modelo 4V (Spectrum )

> Amigos:>> Donde puedo encontrar circuito de monitor AOC Spectrum 4V.> No enciende. Antes de "morir" encendia y apagaba rapidamene, cerrandosehorizontalmente.>> Saludos y mi agradecimiento.>> Luis de Argentina>>>> [Se han eliminado las partes que no son de texto de este mensaje]>>> --------------------------------------------------------------------->      NORMAS DE LA LISTA:> http://www.comunidadelectronicos.com/listas/normas.htm> --------------------------------------------------------------------->>> El uso de Yahoo! Grupos está sujeto ahttp://mx.yahoo.com/docs/info/utos.html>>

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Monitor Aoc 4N (similar al 4S)Web de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      4N (similar al 4S)

      MONITOR VGA      MARCA AOC      MODELO 4N (SIMILAR AL 4S)

      NO HAY IMAGEN. LED AMARILLO ENCENDIDO. RUIDO CHIRRIANTE.      D905 quemado y en corto, en la fuente de alimentación, conectado a la       puerta del transistor FET. Es un TFR155. Se sustituye por un RGP30G.

      INTERMITENTEMENTE MUERTO. (LA FUENTE CONMUTADA NO ARRANCA A VECES, Y A       VECES SE PARA AL FUNCIONAR).      La soldadura de la puerta del transistor FET de la fuente estaba       deteriorada (aunque a simple vista no se notaba, solamente en la oscuridad       se vió una chispa delatora).      

      (C) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Monitor Aoc 4NRLWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      4NLR

      MONITOR AOC

      MODELO 4NLR

      Intenta arrancar, pero se para inmediatamente. El led verde luce durante       un segundo, luego se pone amarillo. Puede oírse un ligero "hipo" de la       fuente al encender.      Transistor de líneas en corto (Q405, 2SC4769, equivalente: BU508DF, aunque       es mejor cambiarlo por un S2055N). Antes de encender el aparato con el       transistor nuevo, revisar las soldaduras de la zona del transformador de       líneas, conector del yugo, etc. que suelen fallar, especialmente en el       conector P401.      Si el transistor nuevo vuelve a cruzarse al cabo de 5 m. cambiar el       condensador conectado a su colector y masa (C419, 4n7 2000 v.), y por       precaución también todos los otros condensadores grandes asociados a la       etapa final de líneas:      C433: 4n7 2000 v.      C432: 680 n 250 v.      C422: 270 n 400 v.      C462: 330 n 250 v.

      INTERMITENTEMENTE, LA IMAGEN (O PARTE DE ELLA) DA SALTITOS EN SENTIDO       HORIZONTAL. SE INCREMENTA EL EFECTO MOVIENDO EL CONTROL DE FASE HORIZONTAL.      Estaba sucio el potenciómetro; bastó limpiar con spray.      

      (C) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Monitor Aoc MM413SWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      MM413S

      AOC MONITOR      MODELO MM413S.

      LA FUENTE DE ALIMENTACIÓN NO ARRANCA.      Sospechar de las resistencias R703 y R704 / ambas 150KW. Estas dos       resistencias están en el circuito que polariza la base del transistor de       conmutación, en la fuente de alimentación, Q701.

      PROBLEMAS CON LA GEOMETRÍA DE LA IMAGEN.      Algunos de estos monitores tienen problemas con la geometría de la trama.       Pero, desgraciadamente, no se pueden subsanar dichas deficiencias --       porque el aparato carece de controles de corrección.

      MONITOR "MUERTO" CON RUIDO EMANANDO DE LA FUENTE DE ALIMENTACIÓN.      En este caso, había tres componentes defectuosos:--      R702 estaba abierta.      * C314 / 2m2Fd, 50VCC (no polarizado) y C708 / 47mFd, 400VCC; sufrían       fugas químicas que habían manchado la placa del circuito impreso.      * Se puede hacer un electrolítico de este tipo, conectando dos de 4m7Fd,       63VCC; en serie -- positivo a positivo (o negativo a negativo) NO POSITIVO       A NEGATIVO. Opcionalmente, se puede reemplazar C314 con un condensador       "normal" (de plástico) de 2m2Fd, 63 ó 100VCC.      

      (c) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Computer Monitor Repair - Archived FilesUpdated 5/1/00All questions and answers posted here become the property of AnaTek Corporation The content of these pages is copyrighted by AnaTek Corporation 1994-2000. This information is intended to be for the individual, private use of all visitors to this site. Reproduction in any form is prohibited. All other rights are reserved.

  QUESTION NO. P1028-6:  CS1572FS monitor FCC ID IAW 1572, no video.   There is High Voltage on the Anode.  The CRT filaments are not lighting.   Where is the CRT Filament voltage derived from?  I checked the CRT with a CRT checked the filaments in the CRT are fine.The Filament voltage (about 6.3V) derives from the the anode of D311 (negative polarity

voltage), and is filtered by C332 = 1000 uF, which often goes bad, so check that cap. But scrape away any of that conductive brown glue, anywhere you find it, power supply, main board, CRT boards, it's nothing but trouble in this chassis. QUESTION NO. P1027-9:  Samsung Syncmaster 3NE monitor, when powered on a low frequency "click" is heard around power supply area.   Power led and screen are off.  When I disconnect it, frequency slows down until "clicks" stop.  I checked power supply transistor and other components like diodes around it, even optoisolator and everything was ok.  I replaced the horizontal transistor which was shorted, no change.Check IC601 = KA3882 (an upgraded UC3842, like the Unitrode UC3842A or Cherry Semi CS3842B), and its associated components. Be sure the supply to pin #7 of IC601 exceeds 16V-17V for the IC's initial startup, and never dips below about 11V thereafter (even transiently, don't trust a DMM reading). If not, check components off of pin #7 (caps, diodes, transformer windings, start-up resistor values), or see if there is a short off the IC's output (pin#6). If good voltages to pin #7 are maintained, check for evidence of shutdown at pins #1 (under 1 volt) or #3 (voltage spiking above 1 volt). It is also a good idea to check all the caps in the power supply for good ESR. QUESTION NO. P1027-2:  Apple Multiscan 15" monitor has no red.  I checked driver transistor.A "Multiscan 15" might be several chassis, but if this one is M2943, the CRT board has been a big problem for loss of colors.  The usual cause is very poor solder, all over the board, and the whole board should be reflowed; double-check the re-solder on the black coax jumpers. QUESTION NO. P1026-6:  I need an ECG replacement for C5339 Toshiba High Voltage of Monitor Acer.2SC5339 is a 7 Amp transistor with internal damper. It is often unwise to try ECG subs for these types in monitors, and MCM (800-543-4330) and B&D Enterprises (800-458-6053) both list 2SC5339 in their stocks, but if you're insisting on an ECG, you might try an  ECG2353. No guarantees, though (and, not knowing which Acer model it is, how could there be?). QUESTION NO. P1022-1:  AcerView 76E 7276e Monitor.  I need a cross reference for a transistor location Q301 part number reads H8 S S 89.Transistor Q301 is a BSS89 F.E.T. made by Siemens or Philips. The Philips device is available from Newark Electronics, among others.  You should also check the following components Q382, J013 (picofuse), C327 (220pF @ 2KV, the original cause of the problem), R326, R241, R328, and R329. QUESTION NO. P1020-3:  Sony CPD-1791 monitor sometime ago displayed hourglassed image when switched on, then turned normal after some minutes. Now the image on the screen remains constantly hourglassed.  I changed the IC TEA2031A, with no result.  It seems the image can in no way be modified by the controls (?) RV251-252-253-254-255-303-304-305-306 on PBG626-5 board.Also check all the SMD electrolytics on the daughterboard for bad ESR, but don't stop there. These caps will sometimes leak fluid that can eat traces and vias underneath the

caps.  Often it is hard to see this without magnification or removing the caps. Depending on what gets eaten, you get different symptoms. If any leaked, jumper any damaged traces and through-hole vias, and clean the board really well, besides replacing the caps. QUESTION NO. P1019-7:  Sun/Sony GDM-20D10 with bad pincushion.   Remote control has no adjustment mode for this.Check/replace all the SMD electrolytic caps on the DA daughterboard, often several are leaky or have bad ESR. To remove the daughterboard, you need only unsolder the four larger pins holding the board in place (one at either end of CN01 & CN02), then it should unplug.  Also, check IC103 = DAC8840FS (Sony part# 8-759-041-45), and IC02 = -5V regulator. QUESTION NO. P1018-3:  Several IBM G50 6543-301 monitors that are dead.  When turned on, they make a high pitch grumble.  I suspect the flybacks are bad. I cannot locate replacements. It is a Sampo FEA-426.Possible sources might be Component Technologies (888-359-2225), ICM (800-748-6232), Cactus Technology (626-357-7979), or Sampo itself, (770-449-6220). In Europe, try ICHE (UK), or AGEA Technologies (France). Or, for a substitute, HR Diemen (www.hrdiemen.es),  email (HR@hrdiemen.es), lists their transformer# HR7933 as an equivalent to FEA426.  Other components implicated in "dead" G50's are, capacitors C162 & C164; the AC bridge rectifer (BR66) and the two 1.5 ohm resistors beside it; R507 = 470 ohms & R523 = 1 ohm near the flyback; Q520 = ZTX948, Q521 = ON4873, Q522 = BUZ11A; the Z200 uProc.; and the front panel keypad. QUESTION NO. P1014-1:  Mag DX17F, the HV has self-imploded, as I see from a lot of reading this monitor seems to do on a regular basis. Could you tell me if MAG-INNOVISION Offers any help that you know of for this rather expensive lemon?   I have several lists of components to check, just started looking.  R177 and L105 are gone. I am sure the High Output Transistor is gone and one on the driver board also popped as I was inspecting it.  Is it worth contacting Mag Innovision for their Upgrade?  Funny, that word makes it sound like a recall and they will pay for the damage their poor design has caused.First, there is not really an "upgrade" for the DX17F, just a standard set of parts that die or get degraded, and need checking, when any individual one goes.  It would be unusual for a manufacturer to consider that situation 'poor design'; there isn't one component dying fast, it's just that a fault kills several of them.  The owner of a DX17F might consider them a 'lemon', but for repair techs, they should  be considered more like 'bread & butter'-- a common failure, with a defined solution, and a manufacturer that is actually willing to sell replacement parts reasonably. I'd take  this Mag over a Nokia, Capetronics, Sony, or NEC chassis with the same symptoms, anyday.  Once more, here's a basic list C120 & C123 (both 1uF/50V); R177 = 1 ohm, R181 = 120K; Q116 = IRF740 or 2SK1378 (depending); HOT Q109 = 2SC4747 or 2SC5048 (depending), D116 = 30DF6 = FR305 or ECG580. L105 is obtainable from Mag itself (p/n# T*I-281-103-UO), or from several parts suppliers, such as LJ Enterprises, Nationwide, MI Technologies, CCS, etc.  Once in awhile, the flyback is bad; bad solder can occur, and other components occasionally do go bad as well, besides the basic ones. QUESTION NO. P1013-10:  KFC CB1414 VS monitor is totally dead.   Tracing through

mains in circ I come to a component which looks similar to a small relay.  It has 3 terminals and is made of 3 copper contacts with 2 discs sandwiched between them. I 'd guess it's some form of diode arrangement.  I have not come acroos this type of device before and need advice about what it is.  It is just before the bridge rectifier in the main 220V line.See the answer for question P923-7, about a similar device in a Proton monitor. QUESTION NO. P917-6:  GVC m1448b monitor manufactured in March 1995, when it is first turned on it is fine then over time it loses color and everything turns reddish or darker colored.This sounds like a thermally-bad LM1203 chip. QUESTION NO. P108-2:  IBM 6321-001 monitor. When powered on it emits a pulsing squealing sound every second or so. There does not appear to be any high voltage. The power light does not appear to come on. I have checked most of the diodes / transistors in the main power circuit. I also checked the HOT on a whim. The HOT seems to have some funny readings.It did turn out to be the HOT transistor that was blown. I have since replaced it and the monitor is now repaired. QUESTION NO. P922-10:  Gateway cs1572fs monitor. Q115 burst and R186 burned, need values.The schematic is too blurry to read the exact value of Q115, it looks like 28665 or 28886 or something close to that. The value of R186 is 100 ohm 5W.The transistor markings(Q115) are as follows:  Top line is "T", middle line is "A1306B" bottom line is date code or something.   R186 is 100 ohms 5watts. QUESTION NO. P108-7:  Two NCD 2082BA monitors have same symptom, scroll back 1/5 of the display, the 1/5 size of vertical at bottorm no light.  I changed the TDA8172, and checked many caps, no change.  Do I need to change the TDA9102C?  I adjusted the vertical linear and center resistance, no change.Check the FCC#, and you will see that this is yet another of those KDM2077 chassis.  Pay special attention to caps C949, C950 = 100uF; they can cause vertical foldover even though they are in the power supply. You might also check out the 600-series 1 uF caps-- C609, C610, etc. QUESTION NO. P108-1:  J'ai des problémes de G1 sur un Sony CPD100sx; impossible de régler la lumiére g1=-174v.Examine R545 = 2.2 megohm resistor, localized near Q507 on the CRT card. QUESTION NO. P917-8:  HP D2804 monitor equipped with crt Samsung M34KUN35X03.  Is it possible to substitute with Toshiba M34KQA23XX06?I save all the picture tubes from monitors I junk out, and substitute freely. Since the convergence is nearly impossible to set up, I leave the yokes on the tube. I can usually lay the chassis on its side and connect up the anode, yoke and ground wire (don't forget the ground wire!) without having to do the whole swap until I can see if the yoke is compatible with the existing drive stage. Surprisingly, about 75% of the time the tubes present no problem and the swap is relatively easy.

 QUESTION NO. P922-5:  MAG Tech DX17F monitor.  In the process of performing the recommended horizontal circuit upgrade for the DX17F, I found that R177 original was .1 ohm, while the faq refers to R177 as 1 ohm.  Is this an intended modification?My schematic lists R177 as 2.2 ohms. It is just a surge protection type of arrangement, and the value is not critical. Be sure to check/change L105. If Q116 was shorted, it is almost certainly fried. QUESTION NO. P922-4:  PB 1512SL Monitor, FCC H4ICM15006, constantly switches between Normal and Standby mode (continuous clicking of RL401).   Checked TP001 for 23.5V and Q424.Almost all the problems these monitors have are caused by the Zilog IC in the front corner of the board going bad. Sometimes the little 8 pin eeprom next to it also goes bad, but I usually try just the Zilog IC first. I'm pretty sure static from the picture tube is what pops these, so I have gotten in the habit of putting a brass shield on top of them and grounding it. I have never gotten one back when I do this. QUESTION NO. P923-7:  Proton PM-1440 (fccBJNPM1448) no power indicater LED, completely dead.  Fuse good,curious about square black component looks like relay, but has grey/silver discs inside seperated by terminals that are solder to pcb.The black rectangular relay -looking box with the disks in it is the degaussing thermistor. It is designed to conduct a lot of current to the degaussing coil for a very short time when power is first applied. The disks will heat up very rapidly, causing their resistance to increase to the point where most current will stop flowing in the coil. They normally will be hot after a few seconds. QUESTION NO. P930-3:  Mag DX1795 Monitor FCC IAWDX17FG Power light, no video, no HV. Tested FBT & Q504 both OK.  Voltages marked on PCB under daughter PCB + & - 12V & 5V OK, 32V = 1.1V.I do not see any reference to a 32 volt line on the schematic. There is a 42 volt source which feeds the flyback/HOT that comes off D314 in the power supply. Do you have this voltage? QUESTION NO. P106-7:  DEC VRC20-HA Digital 20" monitor FCC ID ARFKDM2077 made by Sampo corporation model KDM 207 has full brightness. Brightness control has no effect, contrast works and the screen pot on the LOPT does adjust the intensity of the background. Checked HV 26Kv G1 and G2 are ok. Power supply voltages are OK.Check the capacitor (C409?), 2.2 uF/250V, near the LOPT. If bad, it causes this symptom.  Also, it is advised to check for other bad caps, especially C943, C944, C949, C950; these must be in good condition (low ESR), or there will eventually be trouble. QUESTION NO. P105-8:  Several Philips 4CM4270 monitors with the same problem.  Replaced a defective H.O.T (BU2525) and the +B supply reads 90 Volts instead of 145 Volts. H.O.T becomes hot, no picture.These Philips chassis do not shut-down when the HOT shorts.   Instead, they drop the B+ voltage down. Running like this with a shorted HOT, will damage coils, locations like 5601, 5604, 5613, etc, so check those coils. Sometimes, some resistors also get damaged. 

The usual cause of the HOT originally shorting, is bad solder on the horizontal driver transformer, so also check the transformers out. QUESTION NO. P104-6:  Daewoo CMC-1501BA1 monitor with vertical problems. There is only a white powerful line on the screen.Start by checking/replacing the vertical IC, TDA1675A, and the components associated with it. QUESTION NO. P930-6:  MAG MX15F monitor.  Changed L505, C330, C332, C333, C542, R55, D503 (all new parts).  Monitor now takes 3-4 minutes warm up to display an image.  It will not start horiz unless it sent an 800X600.  Once warmed up on 800X600 (5-10min), I can then switch it to any frequency.Check for conductive brown glue on the logic board.  This can cause many such weird symptoms.  Fastidiously scrape off any such glue that you find there. Also remove any glue in the power supply as well, it will cause problems there too. QUESTION NO. P98-5:  Apple Multiple Scan 17" M2494 monitor.   When brightness and/or contrast are increased, colors diverge horizontally, with green being the most obviously out of line.Possible the crt is weak; blooming?  Convergence should track as with B/W [purity]? QUESTION NO. P101-10:  Proview PV-8500 monitor FCC ID# IJEPV-5640.   No picture, no LED and just a ticking sound from the board.Some of these have that brown glue that gets conductive with aging, and causes such problems on the main board, so remove any of that you find there. After that, go to standard troubleshooting.  Check the 3842 IC's circuitry and the associated switcher FET, and check out the horizontal components (HOT, FBT, CRT, etc). If the CRT is a Samsung tube, check if it is bad first, before investing $$ in a repair. QUESTION NO. P101-2:  IBM 2124 monitor.  When switched on, sometimes a display is shown on the screen.  I checked for bad contacts.  The led on the front is green all the time.Replace ceramic disk cap C335 = 220pF/2KV (it is better to use a 3KV-rated cap), also check the in-series resistor R214 = 15K ohm for damage. Do this soon, before this cap causes your HOT to short out. After replacing C335, run the monitor awhile at a faster scan rate (like 54 KHz), and then check if the new cap has been overheating.   If it is overheating, the replacement cap is not of sufficiently high quality. QUESTION NO. P930-8:  Samsung syncmaster 3 monitor.  Sides permanently curved in and cannot adjust (pincushioning).Change caps C207 and C208, and check caps C206, C210, C211, C280, C301, C302, C307, C316, and C414; also check out IC201 and IC202. Due to a marginal original design by Samsung, C207 should be upgraded from 0.47 uF to a 1 uF/50V value, and install a 1 Megohm resistor between pin 3 and pin 5 of IC202. QUESTION NO. P930-4:  MAG dx1795 monitor lost control of pincushion and trapezoid, screen is hourglassed but otherwise good picture and full control of other parameters. On-screen values appear to adjust appropriately, but no actual adjustment occurs.  Advised by

Maginnovision support to check Q516 and IC701. Q516 appears good, do not have pinout for IC701, so I do not know where to verify signal when adjusting pincusion or trapezoid settings. IC701 is TDA9103 (ST Microelectronics), get its pinout & electrical specs from the PDF datasheet at www.st.com/stonline/books/pdf/docs/1845.pdf. QUESTION NO. P930-1:  Two common problems with Sun/Sony GDM 20D10 monitors - first, horizontal jitter causing fuzzy image.  Second, pulsating parallel vertical wavy lines, which do not cause any picture distortion. Both problems originate in the video board and tend to moderate after monitor is warmed up, but I have been unable to track down the cause with freeze spray.On these units, check/replace ALL (26-29) the SMD caps on the DA daughter board.  Avoid heating or yanking on these SMD caps, twist them off instead, gently twisting back & forth, or the adhesive underneath may rip out PCB traces. Use high-quality replacements, the problem these SMD caps usually get is bad ESR. To remove the daughter board, desolder the four larger connector pins, one found at either end of both connectors CN01 and CN02. QUESTION NO. P929-5:  AcerView 7176ie monitor.  When turned on there is fast clicking and blinking power LED on the front.  Q306 was completely shorted.  I am having trouble finding a replacement transistor.  The case has C5048 on it.  What caused the transistor to blow?The transistor you are looking for is 2SC5048. It is listed in B&D Enterprises catalog, 1-800-458-6053. For the cause check surrounding diodes and capacitors.C5048 is a Toshiba 2SC5048, a 1500V, 12 Amp HOT. Try B&D Enterprises (800-458-6053) or MCM (800-543-4330).  In this situation, always replace cap C307 = 1 uF/50V and ceramic disk cap C320 = 100pF/2KV (it is better to use a 3KV rating); these caps, even if marginal, can cause the HOT to blow. Also check D308, C315, C353, C3950, C3951, C3952. If problems persist, check the coils (L304, L306, L307, L308, etc), check for bad solder in the horizontal area or on the connector pins for the video amp board. QUESTION NO. P928-4:  Gateway dx17 monitor with an arcing crt base.  Burned Q906, R909, R910, ZD901, D903.  What are the values of r909 and r910?  Also what is the equivalent of q906 k526?  Any other parts which could be smoked?You did not say whether your "DX17" is DX17F, or DX17S, etc, but if yours is a DX17S, see Monitor Repair Question# P97-5 and its answer. Still assuming this is a DX17S, to see if the arcing is a bad flyback (more likely) or a leaking CRT, try disconnecting the socket from the CRT, and see where the arcing now occurs-- CRT, socket, or board. QUESTION NO. P927-4:  ASTVision 7N KD-1711 monitor that has resistors R907, R915 and R916 burned beyond recognition. I suspect the flyback is the cause but the label on the FBT is worn.R907 = 10K, 1/2W; R915 = 180K; R916 = 100K. You may also want to check C821, C901, D806, and Q904. For the flyback information and source, contact Korea Data Systems (they made this chassis). KDS's Tech Help phone# is 800-283-1311. You should refer to your monitor as a KDS KD1710 chassis (EVOKD1710). 

QUESTION NO. P924-8:  Gateway 2000 Crystalscan 1024NI Monitor only works at 640X480 60Hz. All color depths function at this resolution and vertical refresh. At higher resolutions or vertical refresh rates, the screen becomes garble and emits high frequency sounds from the monitor.Some older Gateway chassis that read 1024NI on the front will only run at 640x480 and 1024x768. Other modes are not provided. QUESTION NO. P922-6:  NEC Multisync 5fg JC-1741UMA monitor operates normally with sync on green. With separate sync, modes with horiz. freqencies less than approx. 35kHhz are not recognized. Have substituted new control PCB, with same result. Appears to be problem with sync selection processing which is located on video PCB (inaccessible when control PCB is installed).After obtaining schematic of video PCB, was able to trace problem to defective capacitor C8H2, 4.7uf 50V electrolytic, which had decreased in value. This, along with very high ESR, prevented it from coupling discrete horizontal sync to the input of sync processor chip, IC8G3 (except at high horizontal frequencies). QUESTION NO. P923-10:  IBM 6317-001 monitor with vertical problem.   The picture only moves from the bottom not from the top,whereas it should move from the both ends by using the vertical controls.  If the vertical button is pressed to open the picture, it starts shrinking the picture and work opposite of its function.Try checking capacitor C311 = 10 uF/100V, near the flyback. QUESTION NO. P922-3:  CM-335 monitor, when powered on, the horizontal circuit starts but then it cuts off.  The Horizontal Transistor it was subst.If the horizontal output transistor (H.O.T.) was replaced, was the 1 Amp pico-fuse in the B+ line also open? Usually, the 10 uF and 47 uF capacitors beside the horizontal drive transformer (T401) also need to be replaced, when the H.O.T. is blown. QUESTION NO. P922-1:  Daewoo CMC-1427X1 Motitor, the screen rolls unceasingly on all sides like a disorder of vertical hold.  I resoldered without success.See if the vertical signal is entering (pin#4) and leaving (pin#6) of IC302 = Daewoo DW0158-xxx IC.  This is a custom function control chip; if you need one, try NEI, 888-634-7278. If IC302 is OK, check out Q401, IC900, and IC401 (vert. input, pin# 5). QUESTION NO. P910-1:  IBM 8517 monitor works for a while then shuts down.  When I turn it off, wait a few minutes turn it back on it would come back on. Did this for awhile, now it will not come on. High voltage just starts up then the high voltage goes down. Changed a few caps in the power supply. Sounds like the monitor is going into shutdown.Check whether D503 (SMD zener, 9.1 Volt) has gone bad. If bad, replace with either an SMD or thru-hole type zener; zener voltage ratings from 9.1 to 12 Volts should work OK as replacements. QUESTION NO. P98-9:  Apple 1710 monitor, where the brightness is to high with retrace lines and cannot be turned down.Check resistor RCB1 near the EHT. 10 ohm 1/4W.  I had a similar fault, and replaced the flyback before I discovered the resistor.

 QUESTION NO. P921-9:  Mitsubishi HC3905 monitor which appears to have svga input in addition to rgb. If this is svga how do I get it to sync properly?   Does it require a special card or is there some way I can change the setttings so it will work at standard refresh rates?Mitsubishi monitors like this one use a 15HD video cable with a different pin-out from usual, for the inputs into the monitor. Using a typical SVGA video cable will not let it sync properly.  For the special Mitsubishi pin-out, see the Answer to Monitor Repair Question # P827-9. QUESTION NO. P920-1:  Smile 17" monitor, screen does not light up but does crackle after LED goes inactive.  Green active light comes on at power up then goes inactive (orange). A relay clicks back and forth on power up.I encountered the same problem on a Smile monitor FCC ID# GBVCA6736DS which is actually made by "Kuo Fung". This thing is a bear to find exact replacement parts! The problem was originally damper-D104 by the HOT being shorted. I could not find an exact replacement, so I used a FMC G2C. I also found R111, and C125 out of value. As well L102 was leaking. QUESTION NO. P915-4:  Suntomo DB-1765 BA monitor FCC ID# H79DB-1765.  Unit was struck by lightning.  Q101 reads low Ohms on all tests, R101 is toasted.  I need the value of R101.  Looks like a fuseable 1/4 flame-proof.  CR101 tests okay as does NTC101.  Anything else to look for?R101 is a .22 ohm resistor. Double check Q101 to make sure it is good. QUESTION NO. P914-7:  NCD NC2082BA monitor, with (possible) FCC ID LANGF010108M (I've tried this number through the FCC with no results.).  The monitor initializes, i.e., the LED indicator turns from blank to yellow to green. The display shows a video pattern with low contrast (the imagne is covered with white fog).  The screen then begins an intensity oscillation, from foggy display to black.  With each oscillation the intensity of the display increases (the foggy apperance remains, but the display gets much brighter with each oscillation); this continues until a vertical white line is displayed. The unit then fails; and, the power supply begins to cycle.  When I check the HOT; it is shorted. Note I checked the HOT prior to "power on", since many of your submitted problems were associated with shorted HOTs, and discovered the existing HOT was shorted; I replaced it with the OEM Phillips part, BU2527AF, which allowed me to discover the outcome of this behavior, a shorted HOT.I don't believe that is the true FCC#, I think it is probably FCC# ARFKDM2077,  (mfgr. Sampo), and the HOT BU2527AF will be Q730.  With the HOT shorted, also check FET Q714 and ultrafast diode D719. This model is notorious for getting many bad electrolytic caps in the main boards and the power supply; often, over a dozen can be bad or marginal in one unit. For that oscillating display problem, I'd first check the caps in the deflection area, replace any that are marginal or bad. Also carefully check all the caps in the power supply. You probably should just replace caps C943, C944, C949, C950. These four caps must be in pretty good condition (low ESR) for the monitor to behave well. There will likely be more bad caps too. 

QUESTION NO. P915-8:  DX17t II monitor powers up with green light, no hv.  Replaced D101 which was shorted.  B+ reads 180 v,  HOT tests good, good signal to HOT, no b+ to HOT.Besides D101, also check/replace C548, and R173 = 1 ohm. Other suspect components are C117, R212, D109 (Schottky), L105. Also, note that Q106 in this unit occasionally fails with resistive leakiness, not with a complete short. QUESTION NO. P915-9:  Sony CPD-15SX1 monitor.  Switching power supply does not work, no signal to the gate of power FET(Q6) from IC-2 (uc3842AN). The Vcc of IC-2 is ~3.5V.  The relay "click" one time as the power cord plugs in.IC2 (UC3842AN) requires approximately 16 Volts VCC on pin #7 to start.   VCC is usually supplied from the raw +160 Volt primary (line-side) supply via one or two large value dropping resistors. A zener may also be used for regulation. After the supply starts, the VCC is supplied from a diode-isolated low voltage souce via a power transformer secondary winding. Try lifting pin #7 of the IC & check the VCC. If it rises to normal, the IC likely is bad. If it remains low, look for series resistors that have increased in value, a filter capacitor that has decreased in value or with high ESR, or loading components such as a zener or isolation diode that is leaky. It is important to monitor the VCC at the instant of turn-on. If the supply actually starts momentarily and the chip shuts down due to an overcurrent condition, pin #7 will be pulled low & latched by the IC itself until power is removed. If this occurs, troubleshoot the loads on the secondary of the power transformer. QUESTION NO. P914-4:  Xyst 14" Monitor.  Horizontal line appeared in center of screen suddenly. Changed TDA1175 to TDA1175P, no results. I cannot find TDA1175, so substitute with TDA1170N, View restored but picture shrink to only half of normal screen.  Are TDA1175 and TDA1170N changeable? If not, where should I modify it so I can use TDA1170N and get back my full screen view? I cannot get TDA1175 in the market.  I tried to use TDA1175P but cannot.TDA1175 is available from LJ Enterprises (800) 627-8755, however TDA1170N should work as a sub in most instances. Check all electrolytic capacitors in this circuit for high ESR, particularly the cap connecting pins# 3 and #5 (usually 100uF). This is likely the cause of your problem. QUESTION NO. P910-9:  Hewlett Packard m#a4033a monitor with a R858 in the the power supply that is burnt beyond recognition.  It looks like it is a protection resistor for the horizontal driver and output (both are bad).  I need the value of this resistor. H-P A4033A monitor is actually a Sony GDM-20E01. R858 is not a valid location number. Sure you don't mean R588? R588 is 10 Ohms 1/4W flameproof. QUESTION NO. P99-6:  Dell D1028LR Color Monitor ( Phillips Manufacture Chassis CM 6800).  Problem Horizontal collapse, thin line down centre of monitor).  I have checked for dry joints on scan coil connectors etc & continuity of the coils themselves.  I replaced Diode 6632 which was short circuit (BYV 36C).   This was in the scan circuit, however on switch on it has made no difference.According to a technical bulletin from Philips, check R3550 if open perform the following: Replace- R3550 1.5ohm 1/4 w 4822 052 10158, Q7520 mtp6p20e 4822 130 63882, Q7630 BU2527A 4822 130 63627, add Q7523 4835 130 47173 (grid c-12 on schematic,CBA

prescreened and drilled), remove choke L5502, remove jumper 9605 (grid B-12) and replace with a 1ohm resistor 4822 052 11108, add 220ohm (4822 116 83872) from collector of Q7518 (grid D12) to jumper 9128 (grid F8).  This is the second bulletin (and most recent) for this problem.  Grid numbers refer to grids marked on the schematic.    Philips service manual number 6595. QUESTION NO. P99-7:  Magnavox 20CM64BE01 20" monitor with a damaged main sweep, & high voltage module (flyback mounted on this module).   Some of the damaged components were burned beyond identification. I need the part number for the main sweep & high voltage module in this unit & a source for replacement.  Possible part number on the board is 3138 108 82880. I also need the part numbers & values of the following parts also on the same module board for this unit. Coil L 5604, Resistor or Coil 3473, & Var Resistor pot 3660.For a parts source, try NAP (Tennessee), 800-851-8885, they can also ID parts; I found out that coil #5604 is Philips part# 482215763218 (assuming that your unit's FCC# is A3KM020, too...) If they can't ID those parts for which you do not have the location numbers, try the Philips tech help line, 900-896-8324.There is a sevice bulletin from Philips concerning problems on this board and it sounds like it might be what you have.  If Q7605 and/or Q7615 shorted do the following:  replace Q7605 with BU2527 4822 130 63627, replace Q7615 with BU406 4822 130 47377, change C2609 to a 5.6nf 1.6kv 4822 121 43677, change C2608 and C2610 with 4822 124 22676, change D6608 EPG30G 4822 130 83128, add a 33ohm 3 watt resistor in parallel with R3655, replace C2607 with 4822 124 42161, check and replace L5604 (usually burned) 4822 157 63128.  This was a common problem with this set when it was current.   Phillips issued several bulletin until it finally came up with this mod.  Once done, set does not return.  Service manual number 6562. QUESTION NO. P99-5:  Acer 54e monitor, the failure led flashes intermittently.  K2161 blown and when it is replaced and the board is turned on, there is an acute tone that lasts about 3 seconds and then the led starts flashing intermittently and the K2161 is blown again.  Tested the c335, all diodes, transistors and caps around and the hot too and none seems to cause the failure.If the FET is blowing, check if L304 (2 mH) has any shorted turns, also see if rectifiers D316 & D317 are at all leaky, not simply shorted.  The original culprit for many of the problems on this Acer is frequently C335 = 220pF/2KV ceramic; replace it if is at all discolored, or gets warm running, or even on suspicion.  This cap can seem to test OK, and still do damage to several components.  Its series resistor, R214 = 15K ohm, sometimes burns also. QUESTION NO. P97-6:  Radius 0461 monitor FCC # AK8GDM20EO1 is shutting down on startup, with power and power save leds flashing but this time it is the geometry led that is on steady.  What does this fault code mean?  I have not found any faulty components yet but from your previous answers, I have now replaced or checked all the suggested components ( Qs , ICs, Cs, Rs and fuses ) without effect.The GEO light being on, indicates a high voltage failure. If all the FET's, HOT's, and the microfuses were all OK, then the usual problem on these chassis is a bad flyback transformer. But sometimes it is IC801, a 4049B CMOS logic IC, that is bad, and since that

is slightly cheaper, check that first. QUESTION NO. P97-5:  Gateway 2000 DX17S monitor FCC# IAWDX1768SL.   Symptoms; q906 irfi630 , diode d903 5d150f & zener zd901 all s/c.  What is the value of zd901 it is labelled as 12a2 ( 12v??)?  What is the normal b+ on the HOT?  Are there any other components likely to have gone?ZD901 is a 12 volt zener. Besides the parts mentioned, check out the CRT, and check FET Q511, transistor Q512, and signal diode D527. The flyback may be bad, but sometimes rings OK despite this.  Check for evidence of arcing at the CRT socket, and between the H & V focus wires. It is important when adjusting H & V focus pots, not to let the differential voltage between them get too large, or arcing may occur where the wires come close. Q512 should drop its 185V, to about 168V on the drain of Q511. Q906, the regulator FET for the HV generator (Q903), should regulate the B+ voltage at the FBT to about 48VDC at 640x480, 78VDC at 1024x768. The source of Q511, the FET regulator for the deflection HOT (Q503), should be at about 63VDC at 640x480, 98VDC at 1024x768, when it has that proper input voltage of 168VDC at its drain. QUESTION NO. P93-7:  CTX VL700 monitor that has excessive brightness & brightness control has no effect.  Screen control has no effect either. Have checked cap & resistors in Hi Voltage area with no luck.Check out Q336 = Philips JC337-25, signal diode D306, and 12V zener ZD402 for shorts/leakiness, and R480 = 240K, for value. The screen control on the flyback is nonfunctional, anyway, by design. QUESTION NO. P93-5:  Mag DX15T monitor.  I changed a shorted Hot (2SC5129). Over components around that TX mesure OK passively. It works but after about 10 minutes, it seems to get hotter then usual. Is it normal or is there some over marginal component (s) that strains it?Ring out coil L105. This coil is NOT the same Mag part# found in the Mag DX17F; Mag Innovision's (800-827-3998) part# for it will probably be LL*-31L-4LO-*A LSE. QUESTION NO. P93-2:  Qvision 200 monitor, dead.  The first message was HV failure.  I found C839 burnt up and a 330k ohm on the back of the board bad. I replaced both and now it comes up with V out of sync or H out of sync.   It sounds like the HV is coming up and then dies at start up.This is a Philips/FIMI chassis (FCC# GZM). First, bad CRT's can occur, and should be checked for first. Then, besides the parts you replaced, carefully check out the three blue 1.6KV film caps, and also V805, V851, and V852. Best to replace with the Philips' originals, not with subs. Note, the BY584 high voltage diode has a substantial V-forward, so a good diode may well test open on a DMM's diode tester. If the HV failure persists, it's probably the flyback, possibly the focus module. There are three versions of these, depending on which CRT is fitted, so be sure to obtain the same number. QUESTION NO. P92-10:  IBM 9527011 monitor.  We have replaced R143 which was open, as well as T26, T32, and T47. T26 showed signs of excessive heat. We have B+ voltage (160V) but it does not appear to be making it to or through the horizontal circuitry. The B+ is making it to C96.

If you check the FCC number, you will see that this is a Nokia chassis. Check that those FET's are getting good gate pulses. Also, inductor M3 can cook and short between windings, so check out M3. You may need to change the TDA4852 on the microprocessor board. This Nokia has the same problems that other Nokia chassis have (bad solder, bad SMD's, etc); see more details in Monitor Repair Answer# P826-1. QUESTION NO. P92-9:  Packard Bell 1512sl monitor has vertical frequency of about 20Hz.  I changed IC TDA9102C and Z0861404PSC, it did not help. I think that IC 93C56 needs to be replaced, but I do not know what program.It sounds like your particular 1512SL is the Lite-On chassis, FCC#H4ICM15006, not the Goldstar. You buy preprogrammed Eeproms (I703 = 93C56) for these Lite-On's.  A good source is LJ Enterprises (800-627-8755); other possible sources are Nationwide Electronics, or CCS/EDI. Sometimes, I702 = MTV003 also dies, when I701 & I703 both go.  It is a good idea to put a grounded copper shield on top of that new Zilog chip. QUESTION NO. P92-5:  Sampo KDM-2077 monitor has foldover at the bottom of screen. Top of screen is fine. Checked all caps and replaced TDA vertical IC.This chassis is notorious for large numbers of bad or marginal electrolytics.  Do a complete cap check, you'll probably find several dead, and a dozen or more on the edge. Some, like C943, C944, C949, C950, can quickly do widespread damage even if slightly marginal, and probably should just be replaced. For your immediate problem, try cap C609 = 1 uF/250V, but check the others, or it will come back to haunt you.I have found that electrolytic capacitor c949 on the power supply board is the most common cause for this problem.  This capacitor is used to filter the -16V supply which is used for the bottom half of the vertical deflection. QUESTION NO. P827-1:  PV-772IM monitor.  The horizontal transistor C5251 was burned.  I changed it, it ignites several times, but in one of them when extinguishing it, soon it does not return to ignite. One becomes to burn C5251.  I also changed zener ZD601 and C616, but happens the same.It seems to me that either the flyback transformer or all components connected to the horizontal output transistor are at fault.  If you have a flyback tester like the one sold by Anatek, you may find out if the flyback is at fault.In this particular monitor, sometimes, when C5251 repeatedly is blowing, using 2SC5207A to replace the C5251 stops that problem. QUESTION NO. P823-9:  Samsung SyncMaster 3Ne monitor, the horizontal size is too big.  It cannot be adjusted with the potentiometers.Very common problem with this unit. Check Q406, you will probably find the bad solder on its pins.  if this is the case, you also need to replace D407.   It may check ok but replace it anyway. QUESTION NO. P827-2:  Compudyne Kd1500N monitor April 94 factory ID GM, FCC ID EVOKD-1500N. Picture too wide H. position OK, vertical controls OK. H. size control (0-15K) works like a pincushion. Both pincushion, controls, 0-10K and 200-1200 ohm have negligable effect. VR611 adjustment does not help, nor does VR902. Replaced IC' 302 (ECG987) and IC602 (ECG7062) No change. All other connecting diodes, caps and trans.

seem to be OK, except Q306, Q307 and Q308 marked C102, unable to identify do not measure like standard trans. Also, Ic's 303 and 902 are part of this circuity.Check/replace high voltage (160V or 250V) cap C615 = 10 uF, coil L603, diodes D605, D606, and transistor Q611 = 2SD1138. It's also a good idea to check C624, C625, C626 for high ESR and value, besides C615. If one of the two HV caps, in series off the collector of the HOT, has shorted, this will give excess width, but also gives lowered HV and a dim display. QUESTION NO. P827-9:  Mitsubishi Diamond Scan HA-3905ADK Monitor.   Read here that their Cable for Dell/Mitsu monitors is not a standard Cable like for VGA.  Is that true for this model?  I have been trying to align the picture to my test box, but it is all over the screen, cannot seem to sync.Yes, this model uses a different cable pinout from usual, and using standard VGA cables does give that sync. problem. The Mitsu. cable's pinout, on the monitor side is, pin #2 = red; #3= red ground; #4 = green; #5 = green ground; #6 = blue ground; #8 = vert. sync.; #9 = horiz. sync.; #10 = blue; pins #1, 7, & 11 - 15 are no connection. The cable's pinout, on the computer side, is, pin #1 = Red; #2 = Green; #3 = Blue; #4 = ground; #6 = red ground; #7 = green ground; #8 = blue ground; #10 = ground; #11 = ground; #13 = horiz. sync; #14 = vert. sync; pins #5, 9, 12, & 15 are no connection. QUESTION NO. P827-7:   Toshiba version of this Gateway 2000 1572FS monitor has a black relay in right rear that clicks every one second or so after power up. Nothing on screen. Previously responded to flexing the main PCB. Found bad solder at Q105 but repairing this only made the problem unresponsive to flexing the PCB (?).There are a couple FCC #'s for the 1572FS, so I am not sure which your Toshiba is, but, depending on the exact case used with the 1572FS, the plastic bottom can warp from heating over time, and plastic tabs protruding up from the bottom can hit the PC board in the monitor, mashing solder joints. This is especially true, for the tabs on the swivel base case. If this is the case, check and resolder the affected solder joints, and besides Q105, also check / resolder R302, L103, and the yoke connector. To prevent further solder problems, slice 1/8 inch or so off the plastic tabs at the rear. Also, if R331 = 91K is present in the power supply of your version, and is even a small amount high in value, this can cause problems. If it went open, that might even have killed the CRT. If replaced, adjust VR303 to drop 180V across R331. Other potential culprits are C116, C120, Q106, Q301, HOT, D107, ZD307, IC103, IC301, R179 = 20K; some of these also cause no HV, as well as no screen. QUESTION NO. P89-9:  Mag Innovisions NA0503-01 monitor that is exhibiting an intermittent green picture. Acts like a shorted CRT.  Can a B&K precision model 470 be used to test and possibly rejuvenate this tube?  I do not know which tube adapter socket it needs. The CRT number is M36EDR314X360/2F01 it is a Phillips tube.Yes, B&K 470 can be used for testing , even rejuvenating if you are brave (Sencor preferred) shorts remove function seems to work well . There is an adapter for the B&K that uses clips but I forget who sells it . You can wire it yourself using old socket or such.  Connect only one gun at a time using (most likely for your tube) pin 9 ,10 for filament , 8 for red cathode, 7 using red G2 , 5 using red G1 , just move cathode wire to 6 for green cathode and 11 for blue cathode leaving the rest alone.

 QUESTION NO. P826-1:  Nokia 447E090 monitor.  Narrow vertical bar; rutured R195 & R205. What values are these resistors? What other damage should be suspected, if any?R195 & R205 = 215 ohm, 0.5 Watt. In general (some part variations), on the several 447E chassis variants, when these two resistors burn, also check PFET's like T13 & T27, HOT T32, inductor M3 for shorts between its windings, resistors R120 = 100 ohm & R224 = 0.47 ohm, diode D28, & capacitor C121. Also check the various small SMD transistors, like T60 or T65, often marked '3F' = BC857B; these often go leaky or bad, but never it seems to be the same one twice. In the US, Trillium Industries (919-829-9747) carries Nokia coils; you'd need the coil's "FM" number, since "M3" is just a location. The Nokia chassis with thru-hole rivets should have any bad solder on these rivets resoldered on BOTH sides of the board; the bad solder is a common problem with these models.Check transistor T24, a BF422C TO-92, right next to the TDA2040 amp. QUESTION NO. P826-10:  Dell P1728U monitor.  It has a Mitsubishi chassis TB92108801.2.  I replaced the shorted HOT and it worked for about 10 seconds until the HOT shorted again.If you found the HOT Q503 shorted, what was the condition of Q534, the P-FET that regulates its B+? When this P-FET (usually a 2SJ307) goes, it overvoltages the HOT.  Also check for any bad components (diodes, resistors, etc) off the gate of the FET, to avoid more blowups. If, when you say the new HOT "worked", you mean the unit powered on, but you didn't actually see a full display briefly, then it is also reasonable to check the horizontal yoke coil and/or the CRT for shorts as well. If you do need 2SJ307, you might try B & D Enterprises (800-458-6053) or MCM (800-543-4330). QUESTION NO. P825-1:  Xyst FM360 (18021-14021 Rev .06) 14" monitor.  Vertical suddenly collapsed, horizontal still works. Changed vertical amp TDA1175 but no luck.If there is still no vertical deflection after replacing the vertical deflection IC, start troubleshooting around this chip you should be able to trace from it to the problem.  Are both the IC's power supplies (for the amp, and the output) present? Are any associated  components bad? Is there a vertical input? Is there a short, or an open/bad connection or component, off the output or in the vertical yoke circuitry? Get the datasheet for TDA1175 from www.st.com/stonline/books/pdf/docs/1840.pdf The circuit diagrams and pinout should be a help in doing this troublehooting. QUESTION NO. P810-2:  Laser SVGA 14" monitor (Goldstar CA-14 chassis) with a horizontal line (no vertical deflection).  I changed vertical IC TDA1675 to EGC1862, no change.If there is still no vertical deflection after replacing the vertical deflection IC, start troubleshooting around this chip you should be able to trace from it to the problem.  Are both the IC's power supplies (for the amp, and the output) present? Are any associated components bad? Is there a vertical input? Is there a short, or an open/bad connection or component, off the output or in the vertical yoke circuitry? Is there a high output at pin#13 that might indicate a bad yoke circuit? Get the datasheet for the TDA1675A IC from  www.st.com/stonline/books/pdf/docs/1192.pdf The circuit diagrams and pinout should be a help in doing this troublehooting. 

QUESTION NO. P823-10:  IBM 6543-301 monitor (G50), dead.  I have a 45vdc in the hot.  In the power supply I have 166vdc.  I changed IC tda4855 and tda4866 with no change. Also, what is the IC ST6370J5B1/BLI.for this?If the unit is 'dead', check Q520, Q521, Q522, Q603, R102 & R145 = 1.5 ohm, R133 = 0.15 ohm, R424 = 180K, R520 & R521 = 22 ohm, R523 = 1 ohm, the bridge, CR113 = BR66, CR502 = BYV27, and check caps C162 = 470uF/25V and C164 = 1000uF/25V for value and ESR. These two capacitors, when marginal or bad, can cause a host of problems. That voltage of 45 VDC is too low. It could be there's a fault in the voltage boost circuit run by FET Q602, if the FET does not operate. It would be unusual (though not unheard of), for a FET to fail as nonfunctional, rather than shorted, so see if the FET's gate is getting good drive pulses. If not, my suspicion would be to ring coil L600, in series with the FET, for shorted turn(s), that would cause an overcurrent-related shutdown of the driver IC, Z600. But, there's a possibility that the driver IC could be dead, or that it's not receiving its 12V supply (at pin#7). The preprogrammed microprocessor IC, ST6370J5B1/BL, is an expensive and hard to find IC, that, when it goes bad, can cause shutdown problems. QUESTION NO. P817-4:  Sony GDM20SE1 FCC AK8GDM20EO1 monitor no screen, shuts down immediately after powered up. Power  and PS leds flashing, center led solid. Any info on the led combo failure type?In the Apple M1823, a related chassis, flashing power & power-saver LED's along with the CENT LED on solid, is a code to indicate a scan circuit failure. Check the HOT Q512, P-FET Q511, the various microfuses (PS500, PS501 = 1.6 Amp, etc). It is also advisable to check the electrolytics in the power supply main board for bad ESR, leakage, and value, most notably C611 & C612, and several 10 uF caps on the main board.  Marginal or bad caps can overstress the horizontal circuit components. QUESTION NO. P817-3:  I need information on an IC (video amplifier) part number cva2411tx for a Hitachi computer monitor.The CVA2411TX video IC is made by Calogic Corp, and you can get its specs and datasheet from this website www.calogic.com/crt_driver_amps.htm. QUESTION NO. P816-4:  CTX 17" CPS-1760LR monitor.  Upon powering up, I receive four short clicks then it immediately shuts back off.  I have narrowed it down to the power supply.Check the following R109 = 56K ohm/2 Watt, C308 = 4.7 uF/250V, C403 = 22 uF/50V, and C135 [sometimes unmarked, 47 uF/250V, back by the 15HD video input connector].  Besides those, also check Q305 = 2SD386A, Q401 = HPA100, D410 = UF5404, and R353, which are also suspect in this situation, causing video problems when defective. QUESTION NO. P813-3:  In reference to question P628-4 on Mag DX17F, what is a known cross for Q107 (2SK891)?2SK891 is nothing special; it is a 200 Volt, 18 Amp, 125 Watt FET. This can be readily subbed by IRF640 or BUK456-200 FET's. QUESTION NO. P723-8:  Mag DX17 monitor, brightness too high.   Cannot back down enough with brightness control. I turned down "screen" pot on transformer, but brightness was back up again in a few hours. Now brightness control on front panel has little effect,

but contrast control does.You probably have an open resistor in your brightness circuit. (Typically a fairly high value, 100K to 1 or 2 Meg.) I have found this to be a problem on a variety of monitors. QUESTION NO. P812-3:  US Logic MM500 15" monitor suffers collapse & roll gradually after unit is at operatng temp. Only affects 800x600 and higher, Temp is the triggering factor.  I am unable to isolate the specific component, however a fan aimes at front of the PS side of the main board will gradually restore the video within a minute or so.  FCC ID HSUTRLDH-1570 US Logic cat32-10265 Jan 96 Ser# T131859Monitors with that FCC# can get this problem from the TDA9103, a 42-pin PSDIP IC.  Usually, the IC itself is bad, rather than associated parts, and must be replaced. QUESTION NO. P723-9:  Applevision 1710 M3525 monitor.  After powering up, the monitor starts to tick (about 2 ticks / sec ), tube is pulsing in sync with the tick and the LED on the front does the same.Sounds like a classic case of high voltage arcing. If you remove the cover and turn down/off the room lights, you will probably see a spark jumping inside the chassis making the ticking noise.  In most cases, it is just a bad solder joint in the high voltage area. QUESTION NO. P89-3:  Mag DX17 monitor with a shorted Horizontal Output Transistor and VR501 Burnt.  VR501 is a wirewound pot.  What value resistance and is the shorted Hot the reason for its demise?In the DX17S here, VR501 is a 100 ohm pot. However, Mag makes several different "DX17" chassis, including DX17F, DX17FG, DX17S, DX17T, DX17T-II, so your chassis may not be the same. Not knowing which chassis, I can't give any reliable information on the causes, either. You may wish to re-post, using the entire model number. QUESTION NO. P89-5:  Gateway 1776 dx17s monitor has about 1" horizontal collapse on the screen. The width adjustment does not have any effect at all, the vertical is full screen and has adjustment. I have checked all the dc voltage that is marked on the main board.  Is there any factory service menu to check values in the eeprom?Check out Q511 and Q512. I suspect Q512 is dropping excess voltage, leaving little left for the collector of Q503, the deflection HOT. If Q512 has excess voltage and is running hot, but is still intact, trace back from the base of Q512, checking D527, etc. But also check out D503 & D508 for leakiness, the TL082 & NE555 chips near the flyback, and the coils (L504, etc). Also, this model is known for having flybacks that seem to test out well by ringing, but are actually bad. You may need to swap it. QUESTION NO. P89-4:  Macintosh AKA M3502 21" monitor.   Main deflection board went up in smoke, Horizontal output transistor shorted, R113 was open, R109 burnt up, and C106 burned as well.  What is the value of R109? Anything else I should check to prevent reoccurrence of problem?R109 = 22 ohm/1.6W; R113 = 10 ohm/3W; C106 = 0.0056 uF/2KV, 5%, polypropylene.  With those bad, also check C108, C113, C116, C117, C121, C123, C124, C138; U101; V104, V105, V106, V107, & V108. Especially check diodes V105 & V106 for leakiness. QUESTION NO. P730-9:  KDS 1730 monitor, need info or subs for D805, D814.  Both are

marked S2L64, cannot find any info on them.The "S2L 64" rectifiers are Shindengen S2L ultrafast rectifiers, rated 1.5 Amp (50 Amp pulse), Trr = 35-50 nanoseconds. But the "64" is just the date code, which probably explains the difficulty in identifying them. The COLOR of the band on the diode is used to identify the voltage rating red = 200V (type S2L20U), yellow = 400V (type S2L40), blue = 600V (type S2L60).  S2L60 types (600 Volt) could be subbed by rectifiers like BYV27-600, RL4A, SF20J, UF1505 or UF2005; B & D Enterprises (800-458-6053) does list RL4A in its stock. If some loss of speed is acceptable, HER206 (70 nsec) might be tried. The S2L20U or S2L40 types might in addition be subbed by SF24 (200 Volt) or SF26 (400 Volt); Mouser (800-346-6873) and MCM (800-543-4330) list SF24, SF26, and HER206 rectifiers. QUESTION NO. P730-5:  Compaq Presario 14SV 475A monitor (FCC CSYSC-428PTJ) Total loss of sync. Sweep signals are extremely noisy. This can be seen both with the scope and on the CRT. Power supply filtering seems to be OK. High voltage about 22K. Have visually inspected solder joints and resoldered some.A common problem is IC202, a 5V regulator, either having bad solder, or being bad.If you have no Horz. sync and the unit has a squeal to it, check IC202 (+5v regulator) for loose solder. If the sync loss is vertical only, check solder connections on the video cable connector. Both of these are very common. QUESTION NO. P726-7:  Tandy Cm-5 monitor which the end of the data cable has been pulled off.  The circuit board is marked with the actual function of the wire but the color code and pin configuration of the end which connects to the computer are not there. The connector is 9-pin.Borrow a book from the local library and lookup the pinout for the 9 pin CGA/VGA connector for the video output of the computer.  Then wire the cable accordingly. Should be standard CGA codex. QUESTION NO. P729-8:  KDS 17" monitor FCC ID#EVOKD-1730.   Resistors R901 R902 R904 burnt, need the values.Your KDS monitor has the same FCC# as the VTC SC-7 and Princeton monitor for which these resistor values were given, in the answer to Monitor Repairs question # P728-9.  Any chassis with the same FCC number are supposed to be the same electrically (under the law). QUESTION NO. P729-7:  Gateway 1572 monitor  I need a horiz output trans labeled c5129 which does not cross in ECG.2SC5129 is available from B&D Enterprises (800-458-6053) and MCM (800-543-4330), among others. QUESTION NO. P728-9:  VTC SC-7 monitor FCC ID# EVOKD-1730.   Resistors R901, R902, R904 burnt beyond recognition, they come from ABL pin of flyback.A Princeton brand unit, with that same FCC#, has R901 = 27K ohm, R902 = 12K ohm, and R904 = 12K ohm. Probably should also check R903, R919, R948, C902, D901, ZD901, Q901. QUESTION NO. P728-7:  DTK MD-1737 Monitor.  The upper half of the vertical screen is

missing. The lower half of the vertical is good.  The horizontal sweep is good. The vertical output transistor is good. It has a TDA8351 does this IC control any of the vertical?  Should I swap it?Yes, TDA8351 is a vertical deflection IC, with a bridge-configured output stage at pins 4 & 7 (pin 5 = ground). If the IC's power supply and flyback supply voltages, at pins 3 & 6, respectively, are OK, then swap out the chip. That bottom-half-only picture is one symptom that does get seen with defective TDA8351 IC's. QUESTION NO. P728-5:  Compaq Qvision 200 monitor.  Mainboard 82192533563.2 C839 has melted, I need the value for this component.C839 = 470 pF/ 2 KV. Is R910 = 330K/1 W on the solder side of the board also burnt?  Are those three blue 1600 Volt Philips capacitors all measuring in spec? QUESTION NO. P728-8:  Where can I buy a circuit board for an NEC 2143 monitor?  It is the front panel control board<pwe-404b> or Q25-157MS.   I am not sure which one is the part #.  NEC will not sell to anybody.Does not surprise me about NEC after what they have done to their consumer base. I'd contact their customer relations devision and voice my opinion to them about not supplying parts. They stranded millions of cunsumers when they dropped their consumer electronics line a few years ago. I personally do not buy any of their products due to these facts. QUESTION NO. P727-10:  Acerview 34e monitor Model 7134e. I found and replaced HOT 2508AX (shorted) and capacitor 221K/2KV near yoke plug. I hooked up the monitor and it worked for a few hours then the HOT shorts out again.Besides the HOT and 220 pF ceramic cap, check the B+ regulator FET = 2SK2161 or IRFI630, located on the same heatsink as the HOT.  It can get leaky, and deliver excess voltage to the HOT. Also see if R214 = 15K (in line with the cap) is OK, and check out the coils and diodes in the circuit upstream in the B+ supply. QUESTION NO. P727-3:  Two Proview pv1564 monitors, totally dead (no light in power on indicator), and the only sound I hear when power on is from the degaussing.  B+ is 0V, but there is power on rhe FET in the power supply.Is the FET receiving pulses at its gate from the 3842 chip? If not, check or replace the 3842 IC, check any diodes or resistors between pin#6 and the FET's gate, and see that the power supply is providing the proper Vcc voltages to the 3842 at pin#7 (on a scope, at least 16 volts for startup; not dipping below 11 volts while running).  If the Vcc voltages are bad, check any resistors, electrolytics, or diodes off of pin#7.  If the FET is getting good gate pulses from the 3842 IC after all, does its drain react to the pulses, or is it dead?  Also, check to make sure that the current-sense resistor, in line with the FET source, is not open. This model is also known to develop bad CRT's, so if a new CRT would cost too much, check the CRT out first, before going further. QUESTION NO. P78-7:  Tatung 4524 15" monitor.  If I change the graphic mode, the screen size changes and I have to manually adjust screen size.  In DOS mode is working properly.  I have doubt to TDA 9102C/T.The same thing will happen with my digital monitor. Basically the problem is the video card. First make sure you have the newest drivers for your video card.  Second, usually for

new video modes you will need to set the video params manually. These settings are remembered by the monitor as long it is plugged in. If you use a surge protector to shut off everything it will most likely lose its information. QUESTION NO. P722-4:  Orchestra Monitor 15" FCC IDEVOKD-1510.   I replaced a shorted HOT BU2520DF with a C3892A. Runs OK and transistor stays cool but scan is totally out of wack.  Video much too dark, Horz width much too narrow and Vert scan way way too high.  Able to get close with controls but not proper. Changing resolution throws all out of focus and much too bright.Would it be my later type video card?Check out IC401 = STV7778, this IC controls both the horizontal and vertical scans, and the chip is prone to developing problems. You may need to simply replace STV7778 (or sub a TDA9103, if it is more convenient). Besides IC401, you may wish to check the solder on the flyback, and also the components C903, C905, C907, D902, D903, D905, Q407, Q802, Q902. Substituting a 7 Amp HOT (C3892A) for a 10 Amp HOT (BU2520DF) seems like a poor choice, and may cause early demise, of itself or of other components. Since BU2520DF isn't scarce or expensive, why not avoid any doubts, and go back to the original HOT type. QUESTION NO. P723-6:  Viewsonic 21PS monitor, the uprocessor chip is defective. I need the location number or an alternate source.  Also, is the same chip on a 1782-2 ( Viewsonic 17") the same part?  The motherboards of these two monitors are almost identical.You can call Viewsonic at 800-888-8583 for ordering their monitor parts.  For the part identification questions, email vstech@viewsonic.com. QUESTION NO. P721-10:   Je travaille sur un sony 17sf2 ou j'ai changé q507=2sc3997, IC601TEA2262, Q602=IRFPC40, R602=0.22ohm/2W, Q503=IRFI9630 et Q510=FS10SM-18 Maintenant il démarre mais se met en power saving.Examine D596, a signal diode near the flyback transformer, for excess reverse leakage.  D596 is a common problem in the Sony 17SF2 chassis, and one can substitute almost any signal diode (1N4148, 1N4448, etc.). Other problem components to test are C525, C540, C541, C592, and IC904 = TDA9103. Because Q503 was defective, also examine Zener D505. QUESTION NO. P722-6:  Gateway CrystalScan 1024NI monitor, Ch#cs1024NI2 and FCCID#IAW.  Replaced shorted HOT. D502 on M'Board was blasted, I need replacement ID#, please. (Subbed a best guess diode and set ran for 2 minutes, then subbed diode shorted out.) All other static tests appear OK. Any other chronics I should know about this chassis?If the OEM D502 was marked 15DF, it is a fast recovery (<150 nsec), 1.4 Amp rectifier.  Did your sub meet this spec? An ECG/NTE 571 rectifier ought to sub for these, or perhaps an HER207. The 1024NI2's notable failure is, that increases in value of R325 or R335, in the power supply, cause supply overvoltages that damage ZD202, R241, R334, electrolytic caps in the center of the board, and the vertical IC & its assoc. caps.  QUESTION NO. P720-3:  IBM G41 monitor with two transistors that I need a cross ref for;

ssh5n90 and Dn or ON-4873.SSH5N90 is a Samsung FET, TO3P case, 900 Volts, 5 Amp, 150 Watt. A possible cross would be 2SK1358, or maybe 2SK872, available from MCM (800-543-4330), B&D Enterprises (800-458-6053), etc. ON4873 is a Philips HOT, and LJ Enterprises (800-627-8755) has carried this OEM HOT. It is never a great idea to try to sub a HOT, and that's also true here, but if you get stuck, try a Philips BU2520. QUESTION NO. P78-1:  Need cross ref for the following components from a HP D2830A monitor (FCC ID# A3LCGC560); Q503 (C5386) and Q407 (C5002).Usually, these would both be Japanese "2SC" type transistors. But that FCC number indicates that this chassis is a Samsung (Korean) chassis, and that complicates matters. Toshiba (Japanese) makes a 2SC5386 horizontal deflection transistor (1500Vcbo, 8 Amp, 50W), but, in a confusing coincidence, Samsung itself also makes KSC5386 (1500 Vcbo, 7 Amp, 50W). The two devices are not interchangeable, because the Samsung device has a damper diode, the Toshiba does not. So it is important to determine the transistor's manufacturer, for example, from the logo on the device. A possible sub for the Toshiba 2SC5386 might be Sanyo's 2SC5297,  while Samsung's KSC5386 might be subbed by Sanyo's 2SC4123. The "C5002" most likely is Sanken's 2SC5002, rated at 1500 Vcbo, 7 Amp, 80 Watt, esp. if it has an "SK" logo. B&D Enterprises (800-458-6053) lists this Sanken, and both the Sanyo, transistors. QUESTION NO. P716-8:  IBM 6543-301 monitor.  When turned on, it turns the high voltage on and there was a picture in about 5 seconds but, after turning it on and off 20 times at does not even start the high voltage any more.First check/replace C162 & C164 in the power supply. These capacitors can cause problems when marginal, and eventually can kill other parts, so also check resistors R424, R507, R520, R521, R523; transistors Q520, Q521, Q522, and Q600; and diode CR502.  If none of these parts are faulty, the bad news is that the CPU IC, Z200 = ST6370J, also commonly marked "IBM PLUTO", is a common and expensive failure item for shutdowns in this chassis. QUESTION NO. P716-2:  IBM-2124 (FCC JVP7154E) monitor also known as Acerview 7154.  Need replacement for L304 2mH measured at 768uH and a source.Try a Mitsubishi, or an Acer (FCC#JVP) supplier, part number 19.40133.001 is L304. In the US, Gastron Technology (626-813-1503), ICM (800-445-1503), and Marcus & Assoc. (800-445-1503), among others, have carried Acer parts. QUESTION NO. P715-10:  Goldstar 1727 monitor, CA-27 chassis.   Need the value of R448 that has burnt.R448 = 390 ohm. Resolder the connections on Q405, that's probably why it burned. QUESTION NO. P72-7:  Philips C2082DAS/II monitor whose line transistor THD4oo, serigraphied V815, on the main board, is in short circuit. I cannot find its characteristics or an equivalent.  I have checked the flyback capacitors, they look good.ST Microelectronics has obsoleted the THD400. If this is the Philips unit made by Fimi (FCC# begins with GZM), it has been suggested to modify the chassis to accept a 2SC3998 for V815 replacement. In addition to the installing the 2SC3998, which will need a retainer

clip, and mica insulator with heatsink grease, the modification also requires removing V841, C883, and C884, and installing a jumper wire in place of C884. Be advised that if the THD400 shorted along with other faulty components, the replacement may also blow, if those are not also fixed. Check out R807, all the HV rectifiers = all "BYV" types, & BY584 (this one has a Vforward > 6 Volts!), all the HV Polypropylene snubber caps, microfuses, and coils L807, L802, L803 (T803, & R910, if present). Other common failures are the focus assembly module (gives focus/brightness fluctuations), or the flyback itself (HV-Failure). QUESTION NO. P628-6:  Two Sony CPD-100GST monitors.  When computer is on and signal cable connect to it, power green LED comes on, high voltage on, but screen is black.  I see RGB on input pins of preamplifier CXA2055P but not see on output.  I replaced CXA2055P but nothing change.  Could it be the Microprocessor chip bad?CXA2055P is an I2C Bus-controlled RGB preamp IC. So, this IC may have been put into a shutdown mode by the microprocessor deliberately, for an unrelated fault, or some component along the I2C bus line may be faulty. First, check the obvious. Is the CXA2055P getting both its 5 Volt (pin#7) and 12 Volt (pin#20) supplies? Is there any blanking input coming in on pin#16 (>1.5V)? Is there a good clock signal for the I2C logic coming in on pin#2? Is there I2C data being received on pin#1? Commands, received via the I2C bus, control all parameters of this IC's output. If the IC is being shut down by commands off the I2C bus, download the datasheet to get the I2C command codes, from http//www.sony.co.jp/~semicon/Datasheet/en/a6801860.pdf. QUESTION NO. P79-9:  Two Gateway Crystalscan 1024NI Model #PMV1448. Both of them seem to have a problem with the vertical display. On one of the monitors, the vertical display is about half an inch wide while the other has about a four-inch vertical display.  The horizontal display seems to work fine on both of them. On the monitor with the smallest vertical display, I replaced the vertical circuit transistor but that did not change anything.Check IC201 = TDA1675A for shorts. Be sure the supply on pin#14 is at least 21 V; if not, check components on this line. Check height adjust (pin#7), and components off pins #1 and #12. If not already done, do this modification change jumper J118 to a 1K resistor. Change C201 from 47 uF to 220 uF/35V. Remove any conductive goop around the tiny ceramic caps, like C204 = 0.1 uF/50V, in front of IC201.Try removing the "peanut butter" like glue from the vertical circuit. This has worked for me in the past. QUESTION NO. P79-2:  Tatung TM6714 17" monitor, picture vertically discomposed.  Change caps in power circ.,but no resp.Check capacitors around vertical TDA 1675,esp.C305,306. QUESTION NO. P78-10:  Gateway cs1572fs monitor, squeals and has wavy horizontal lines through rastor.  This question was asked before and two different answers were given.  It is not the B+ voltage or R329 which do not match those that are the main circiut board.The problem resistor in the Gateway 1572FS chassis with the FCC# IAWLX1564 is resistor R331, which is 91K ohms; if it gets above 95K ohms, it can cause squealing and

waviness. Use a precision, 1-2W replacement type. Also check R335 & R336, 180 ohms, and R503. Sometimes, VR303 needs re-adjusting, to get ~180V at R331, to remove all the lines from the video. Zener ZD302 (12.2V to 13V) can be a problem when R331 is not the fix. Also check C116 = 10 uF/50V & L106. The Gateway 1572FS chassis with the FCC# IAWLX1572 should be checked for conductive glue problems. QUESTION NO. P78-9:  Older CTX 17" CPS-1760LR monitor. After fixing some bad solder connections on the power supply, I got it to work but the sides are curved in like question marks, and I cannot adjust the horizontal size.Depending on the exact board version, some parts will vary a bit. Check C135 = 47uF/250V (sometimes unmarked), nearby to C139 and the HD-15 data input plug.   Check D410 (ultrafast type, UF5404), pin amp Q305 = 2SD386A, C308 = 4.7 uF/250V; R353 = 10 or 22 ohm/2 Watt; R304 = 33K; R316 = 1K. Check solder on sub-boards and the connections to the main board. QUESTION NO. P68-3:  Lite-On KM411 monitor, blue color is missing. I check RGB unit but I did not find the problem.Scope the color signals along their way from the VGAplug to the board on the neck of the pcb. If there is no scope available take advantage of the fact that the circuitry processing the three different colors is the same for R,G and B. So try and interchange the signals (missing and present) at strategic points like cathodes of CRT - RGB from chassis to neck pcb - output of color processor - input of color processor - right at the VGA plug.The problem is TLS1233N. QUESTION NO. P77-2:  IBM 2124 monitor. The horizontal output Xister was S/C. Replaced ok. When fired up a small disc ceramic cap off the Collector of the H/output Xister was s/c. This caused a resistor connected to the cap to burn open. I measured the B+ at voltage a the H/out collector and only had 50 DC.  Also no base drive to the H/output.  What is the value and working voltage of the disc ceramic cap?  What is the vaule of the 1/8 watt resistor connected to the cap?  What should the B+ voltage be at the Collector of the H/output?  Where is this voltage fed from?+?If the FCC# on this IBM is JVP7154E, then the ceramic cap is C335 = 220pF/2KV, the resistor R214 = 15K ohm. In VGA mode, expect the B+ at the HOT collector to be around 78 VDC, with 1200 Volts peak-to-peak. The FET for B+ regulation is mounted on the same heatsink as the HOT, but check out both Q316 and Q317, also coils L304 and L305 and assoc. components. QUESTION NO. P77-9:  Acer 7176ie monitor.  Replaced c3950, c3951, c3952 for intermittent video problem.  Now unit has no horizontal size or pincushion adjustments.  All other functions work ok.First check ultrafast rectifier D308 = FES8JT (600 V, 8 Amp, Trr < 35 nanosec); if it is leaky, it is $4.34 from B & D Enterprises (800-458-6053). Always replace ceramic cap C320 = 100 pF/ 2KV. If D308 is not the problem, check out transistors   Q310, Q312, Q313, Q314; diode D307; caps C609, C610, C623; coils L306, L307; IC301. QUESTION NO. P72-1:  I need a source for replacement back lit lamps for Toshiba notebooks. They are very tiny, about 2-4 mm in diameter.

If you insist on a new exact-replacement lamp assembly, dressed out to fit your model notebook, the source is probably going to be Toshiba. Toshiba sells the lamps for $150+ apiece, given the proper part number, which depends on whether the LCD display ass'y. is truly made by Toshiba (like p/n# P000197200), or is a Sharp display (like p/n# P000194950). If a Toshiba service center actually does the repair, they will probably want to replace the entire LCD display, for an astronomical price. If you can accept a close match on the lamp (and sometimes maybe having to drill a mite with a Dremel tool), JKL Components Corp. (Pomona, Calif., 800-421-7244) is a domestic producer of these CCFL lamps. Pick the closest matching tube from their website at www.jkllamps.com/fluorescent.html Their bulbs and accessories are $10 - $15 from a distributor like Digikey. If the bulb is damaged, or failing, you will need a new one.   If the bulb does not light, but isn't damaged, it may also be a bad inverter, or a cheap fix like an open fuse (incl. any SMD fuses on the inverter board), or an open thermal fuse or electrical connection. These inverters are HV & high frequency, so watch out for RF burns, and keep any leads short. For more information, see the JKL home page at www.jkllamps.com , or the answer to question P622-1 on the Monitor Repair page. QUESTION NO. P69-1:  Acer 7176IE monitor, will not power up, and there are no lights lit.  I have 83vdc to the fet.To answer my own question, I found Q601, shorted ebc, then IC601 had only 3.5v on pin 7. replaced q601, ic601, and, had 11.5 volts on pin 7.  Replaced c605=22x50v, this allow the monitor to power up. At this time there is 17.5volts on pin 7 of ic601, and, all is well. Replaced c607=100x50v while you are there.To add to my answer there was 167v on the drain of fet.  This monitor came back in three weeks with the same problem of no startup.  I found that d603 [1n4001], causes a low voltage condition at pin 7 of ic601.  All other componets checks out to be ok. QUESTION NO. P628-1:  I need a description of q5e4 in mainboard of nec multisync xe15 monitor.Q5E4 = 2SD1763. An NTE2576 would be a close substitute for that type. QUESTION NO. P628-8:  AOC CMLB-736 monitor was dead.  After changing Q804 2SC3996 and Q805 which were short cicuit, the set worked for short time with reduced width and Q804 running very hot.  The HT voltage seems to be correct and I have checked the capacitors around the HOT.Replace C821 (between T801-HO-Driver and Base/HOT) 4,7µF/35V. QUESTION NO. P628-3:  Apple multi-scan 20-inch video monitor, model M1823, powers up briefly, then shuts off, with yellow light blinking. High voltage comes up, at about 25 kV, apparently normal. Vertical sweep OK (vertical bright line) but no horizontal sweep during the brief period before total shut down. Pulses to base of horizontal drive transistor are present, but about 100 kHz, even though h-sync from computer is only about 25 kHz. Problem? Collector of horizontal (yoke) drive transistor floats up to about 70 VDC, then, when sync pulses start coming in to the base, suddenly drops to 0 VDC. Part of shutdown, or cause of shutdown?First, if you are using a Sencore, be sure to use the special adaptor for this Apple unit.  Check for open Sony microfuses, PS500, PS501, PS800, etc. Check P-FET Q511, and also

the diode installed between its source and gate. A bad Q511 may be leaky, shorted, or it may simply not turn on properly, so besides ohms-testing, see if its drain responds when the unit is sending pulses to the gate. Check R851, R868, and C822. Also, do a general check of caps in the power supply; usually some are bad for ESR or value.  Other common problem components are D824, D825, IC404 = TL082, IC801 = 4049B, flyback. QUESTION NO. P628-4:  Mags DX 17F monitor, Q109 was shorted.   Replaced transistor unit worked Ok. When turned on from cold no horisontal drive to base of Q109.When Q109 blows in this model, several other parts MUST be checked or replaced, because any parts that died can then kill other parts, as well as any replacement parts.  You should also check or replace caps C120, C123, C147 (at the very least); coil L105; resistors R177, R181, R939; fast-recovery diode D116; and FETs Q107 & Q116. If coil L105 looks even slightly cooked, get a new one from Mag. Caps C120 and C123 should probably just be replaced regardless, and also R181 if its value has changed. Replace Zener ZD107 (6.2V) if it is below 6 Volts. HV is nominally 27 KV (HV adjust is VR105), and the HV shutdown is set for 29.5 KV (trip adjust is VR106).   Occasionally, the flyback transformer is bad. QUESTION NO. P622-1:  Where can I buy replacement fluorescent bulbs for a Toshiba 315CDS laptop?  I believe it is a Dual scan passive matrix. The bulbs is displaying very bright areas across the bulb and as a result the picture has bright streaks. I temporarily put black tap over the areas that are the brightest and that did the trick. I would like to still replace the bulb though. It does not have any kind of number stamped on it. The bulb is about 10 inches long and about 1/16 of an inch in diameter with wires mounted already on the ends with rubber boots.If a lamp with a 3 mm diameter will fit the unit, Digikey (www.digikey.com) carries CCFL lamps from JKL, at about $11 apiece. You need the lamp's exact dimensions in mm. to choose the correct size. An exact sub (but used) might be obtained from www.buylcds.com Those would cost about $55 apiece, but a new CCFL lamp from Toshiba would probably be several times that price. Also, any lamp that's not physically damaged, should have its inverter checked out as well (JKL's inverters are also at Digikey, $15, plus optional connectors, $2-$3). QUESTION NO. P68-2:  IBM 6542-103 (G40) 14" Monitor is unbearably fuzzy.  External controls (contrast & brightness) have only slight effects. Have been unable to find schematics. Have found Vertical/Horizontal hold.   Hoping to find focus.Focus control is located on the side of the flyback. However, if the focus adjust also raises and lowers the raster you have a bad flyback and it will need to be replaced. QUESTION NO. P622-3:  10 IBM G41 6542-301 Monitors, all have problems.  Where can I find service information on these?Try M. I. Technologies, www.mitechnologies.com (document 2884-L). QUESTION NO. P67-3:  Where can I find the amplifier/buffer for RGB tht is an Hitachi made FA4111 for a Sony monitor?B & D Enterprises (800-458-6053, www.bdent.com) is listing Hitachi's FA4111 for $23.46. 

QUESTION NO. P617-8:  Gateway 2000 1024ni monitor with very poor horizontal sync.  I have confirmed 12 volts dc getting to the horiz. osc. ic.   Static tests on components have so far been unrevealing.If your 1024NI is the 1024NI chassis made by KDS (FCC# EVO), and the symptom is horizontal jumpiness and unstable image, check/replace the control pots on the front panel, esp. those for Horizontal Size & Phase control. They are of low quality, and are known to cause that symptom. QUESTION NO. P617-6:   Princeton EO40 monitor does not have vertical deflection.  The IC tda8351 was replaced, no change.Troubleshoot it using the voltages on the TDA8351 (pin#5 is ground). Is it getting any Vp (9V-25V range) on pin#3, or Vfb (up to 60V) on pin#6, the output supply?   Is the differential input signal coming in on pins#1 (+ input current) & #2 (- input current)? Or is the Guard circuit activated, and showing 4.5-5V on pin#8? A high voltage on pin#8 shows the IC is deactivated, for one of these reasons; an open circuit (bad connection or open component), or a short circuit between the output pins #4 & #7 (like a shorted vertical deflection coil), or from one output to ground, or (less relevant) from a thermal overload or during flyback. Does the sense resistor between pins #4, and #9 (the feedback input), show a sawtooth voltage waveform? QUESTION NO. P614-10:  AOC CM335 monitor is dead and the internal fuse is okay. There are no obvious burnt components or dry joints on the boards. The power on lamp is not lit and the switch checks out okay. The thermistor is warm to touch when on for a while. Are there any typical problems that I may check before I suspect the LOPT.The usual cause of the AOC CM335 PSU not starting is a high or o/c R907/R908. If the HOT is shorted replace C512. Also replace C512 if the HOT runs too warm. QUESTION NO. P615-9:  Proview PV 564D 15" monitor.  You can barely see the screen with the contrast and brightness adjusted to their max. The images on the screen do not appear distorted just very hard to see.Bad CRT's are very common on these, esp. if it is a Samsung CRT. If the heaters have a solid 6.3 V, and G1 & G2 aren't too low, then 100 to 1 that it is dim from a bad CRT.   Replace it, there's no point in trying to restore bad Samsung CRT's. QUESTION NO. P614-5:  Mag DX17 monitor, has no high voltageand shorted hot.  Taking advice on this page of tips I replaced several parts including c123,c120,q109,L105,r177,d116,q116,c908, r181 checked good.  The tech tip also makes reference to q103 2sd1887.  I have searched and searched to find it on the main pcb to no avail.  Is there such a part and were is it hidden?This is an error, for 2SD1887 is a HOT, and the HOT is Q109 in the Mag DX17F. QUESTION NO. P518-7:  Philips 14A monitor, connected with computer. noe.  The led can turn from yellow to green, but no HV.  Second power FEt5P25.  There have about DC 180v voltage in "S","G' ,but no voltage in "D".Although number for the FET is not complete, it is possible to tell that this FET is a P-channel type. With the same 180V voltage at both the gate (G) and the source (S), this P-FET will not turn on. So trace back from the gate input, and find out why the gate drive

circuitry is not functioning. QUESTION NO. P68-9:  Packard Bell 2020 (FCC ID DK42020; GVC Corp.) monitor, 10 electrolytics are removed from the main board and I need their values:   C316, C321, C322, C402, C406, C407, C411, C416, C417 and C439.C316=100/16;C321=47/16;C322=10/16;C402=4,7/50;C406=10/25;C407=10/50;C411=100/16;C416=47/16;C417=47/16;C439=3,3/50V. QUESTION NO. P68-10:  CTX 1451 Monitor came in with power supply overload (click-click) problem.  Replaced bad HOT.  Now image has horiz foldover, raster pulled in one-two inches on each side.  All controls work except horiz size - provides minor variation but has equal/opposite effect on vertical size.There are several different chassis for CTX1451 (different FCC #'s), so these locations cannot be guaranteed, but if C722 = 47uF/50V, test/replace it; also, R434, D104, Q406, Q407, and Q410 should be checked. QUESTION NO. P67-2:  Aoc 17" modèle 7Hlr avec q420(bu2525ax) en court circuit et r113=1ohm/1w coupé mais tout grille de nouveau aprés quelques minutes de fonctionnement.I believe this chassis is the same as the Royal 1782 model (FCC# HSU). The usual problem is the horizontal driver transformer has a defect, and overheats Q420.   If you cannot rewind the transformer, or find a replacement, one trick is to solder a second capacitor = 10 uF/63V in PARALLEL with C476 (near center of board, below Q411). This should cause Q420 to run cooler if the transformer was the  problem. Also check R498 = 1 ohm/2 Watt, Q414, T403, FET Q103 and the black cylindrical coil close to this FET, and the diode in series with R113. QUESTION NO. P64-1:  Two 15" Voxon monitors that need the Horizontal Output Transistor marked 2520DF.No cross reference found. I 'd also like to know where I can get a service manual.  Another 3 monitors of the same kind only display the upper half of the screen(lower half is black).That will be a Philips BU2520DF, a transistor with an integral damper diode; there are many possible sources, among them MCM (800)543-4330 and B & D Enterprises (800-458-6053). Also test the flyback after replacing the HOT. Without having any model numbers or FCC numbers, there is no way to get specific about your symptoms, or sources for manuals. If the FCC number is present, look up the manufacturer from the FCC number, and try them for manuals. For the units with vertical collapse, if these only have shrunken video, but are syncing the video properly, try testing the vertical IC with heat or freeze, or swapping it out. If, however, the remaining video in the top half is not syncing correctly (rolling, lines in the video, etc) and if those units also have a TDA9103 or STV7778 IC, those IC's can cause that kind of symptom when bad.With respect to the voxon monitors with the vertical problems, I just repaired one with same symptoms by replacing the C3205 transistor near the vertical output IC using a NTE-11. Replace it even if it checks good because it breaks down under a load. QUESTION NO. P524-6:  HP-A4033 (GDM-20E01) monitor.  See answered question P510-5. I replaced Q511, IC404 and checked all the caps per answer. Turned the unit on

and everything was fine for a few days. Upon power up on day 3 the Win98 Splash screen was fine from the center of the screen (top to Bottom) to the lefthand side. From the center to the righthand side it was way out of focus (top to Bottom). As it warmed up I could see the focus getting better and then just as it was almost all in focus, the picture died and I heard the screach again. I took it apart and found Q511 and Q512 to be ok. R470 was burnt (but not open) again. Is 1K the right value for this resistor? I cannot find any bad or leaky components.Probably a bad flyback, foucu pack, and/or crt. QUESTION NO. P526-10:  IBM 6543-301 monitor (G50) with no high voltage in the hot.  There is 45vdc and 45vdc in the neck board.  When I start the monitor the led blanking "green orange".  I changed the IC number tda4855 and tda4866 with no change.  Also, what is the pin out for IC ST6370J5B1/BLI.Is there B+ at the collector of the h output or B+ terminal of the flyback? Is there B+ at the collector of the h driver transistor, do you have any HV at initial startup or does the unit totally refuse to produce any eht? What value is the regulated B+ from the smps? It should measure roughly 125 - 130 volts. If there is no source to the deflection ckts then look for probs in the regulator/smps. QUESTION NO. P64-7:  Princeton EO75 monitor, HOT shorted 2SC5270A. Need specs or substitution. It appears that Princeton eventually substituted another part for this transistor because of repeated problems.2SC5270A is a Matsushita HOT, rated 1600 Vcbo, 12 Amp, 120 Watt max. Tfall is typically 0.12 usec; Tstg is typically1.5 usec; gain is 5-12 (8 typ) at 6 Amp Ic; Vce[sat] is 3 V max. (1 V typ) at 6 Amp Ic/1.5 Amp Ib. It has a TO3PE case, for which that max. wattage rating is very high. This, with the 1600V Vcbo rating, make this one difficult to sub exactly. But, MCM (800) 543-4330 does list 2SC5270A itself for about $9, and B&D Enterprises (800) 458-6053 for about $13. QUESTION NO. P526-5:  Nec JC1741UMA monitor, the power light is on and the tube sounds like it is charging but there is no picture on screen.If there is power and high voltage, but no video, one cause is forgetting to put the Sync switch on the back panel to its "on" position!   Also, check that the BNC/D-sub selector switch on the front panel is set correctly. QUESTION NO. P526-4:  Several Compaq model 471P FCC ID CSYSC-428VSA have vertical def problems. The problem is the IC201 and the heat sink compound was dry (TDA8351).  The IC seems to be heating up.  All caps in section are good.  I checked it and it is about 145 degrees.  Is that normal?This Samsung chassis is notorious for burning up vertical IC's. There should be a resistor (R201?) off pin 6 that may also be damaged, the exact resistor value will vary depending on chassis version and CRT yoke installed. Any caps off of pin 6 should also be checked.  You may need to adjust the B+ voltage to pin 6, or play with that resistor's value, to get the IC to run cool now with the other (aging) components; too low a value for that current-limiting resistor, or conversely too high a B+ voltage to pin 6, can cause the IC to overheat. You should not be exceeding 36 Volts to pin 6 of TDA8351, if adjusting the voltage. Try starting with a resistor 50% higher in value than the current value, if you're trying a

different resistor. QUESTION NO. P430-6:  Mag Innovision 17f monitor, has a jitter that occurs once in a while slightly and close to the middle of the screen there is a line going from top to bottom.  I replaced everything in the kit except D116, Q116 ,Q103,and C908. Each of them tested good. I am going to replace C908 anyways.Usually a bright vertical line toward the center of the screen is in indication of a shorted winding in the yoke. Occasionally a winding in the Flyback can produce a similar result. The bright line accompanies or is a precursor to a folded image in that area.The Mag DX17F has a line in the center of the is commonly caused by the wrong h.o.t or a H.O.T going bad.  I have seen 2sc4747, 2sc5048, 2sd1887 transistors listed. I tried interchanging these and in every case when the one that came originally in the monitor was changed to one of the others it caused a faint verticle line located in the center of the screen. The line location changes with resolution and becomes two lines at 1024x768 and higher. QUESTION NO. P430-4:  Nec 5D monitor with no power LED, no heater in picture tube, but has hi-voltage present on front of screen.  Power supply checks out, 170v, 85v, and 24v are present.The NEC 5D gets its filament voltage (6V) from the Video input board, that is the board nearest the back. If you trace the twin ribbon cable from the CRT board to this board you will see where it is fed from. The six volts is fed through a resistor which ultimately derives it's supply from a 12 volt source. I think you will find a 12 volt regulator on this board that is supplied from the 24 volt source coming into the board. This is a common problem. Also check all components from the 12 volt regulator to the 6 volt feed. A schematic REALLY helps, since this board has circuit traces on both sides.  The power LED also will not light when this circuit does not work. QUESTION NO. P524-2:  AOC 4Nlr monitor. It works fine in DOS and Windows at 640x400, but at 800x600 the picture rolls.Check out IC201, the Weltrend WT8042 chip, as well as its crystal/resonator, and any associated capacitors. LJ Enterprises, MCM, and others carry these IC's. QUESTION NO. P518-9:  Acer 7156 monitor.  I replaced the flyback and got the monitor back to life.  But now the picture is about an inch too wide and the front panel horizontal control does not have any effect, nor does the pot inside the monitor. The rest of the digital controls work perfectly but when pressed the one corresponding to the horizontal width all the green LEDs flash weakly while pressing the button.This symptom is usually caused by a shorted diode in the horizontal output circuit. Thoroughly check all diodes, especially the larger ones around the flyback area. Occasionally the Horiz. Output Transistor will short B to E. If the output uses a transistor with an internal damper diode, it will show shorted anyway (to a meter). However, if the output does not have an internal damping diode, then it should not show shorted B - E. The Horiz. and High voltage will often still operate even though the output transistor is leaky or shorted. QUESTION NO. P514-6:  Highscreen MS1457 LE-II monitor.  After 15min picture gets darker and out of focus, no significant change in picture geometry. Vendor's diagnosis was

'CRT bad', now customer wants second opinion.  I would think of screen divider/flyback/eht being at fault. Monitor was operated at ~48khz h-scanrate. Overheated/cracked flyback?Check the HV and focus potentials, make sure the focus voltage does not change when adjusting the G2 bias. Check the voltages with and without the crt connected. That is with the anode and crt socket attached and removed from the crt. Make sure the regulated B+ is correct to the deflection ckts also.  QUESTION NO. P511-2:  Mag DX17 Monitor suddenly lost focus and got slightly brighter (no noise or burnt components).  Turning down HV and adjusting focus and screen restored focus, but picture is now darker and smaller.This could be either a defect in the screen/focus voltage divider section of the flyback, or some conduction may have developed between the focus and G2 grids within the CRT. If the focus and screen controls were interacting, and affecting each other's function while being adjusted, this would favor leakage between the CRT grids. In that case, see Anatek's Tips & Tricks webpage, for a trick on how to "zap" the CRT pins and clear these kinds of CRT shorts. Or, if the flyback has developed a leakage of high voltage into the screen/focus divider, replace it. QUESTION NO. P520-5:  Several Orchestra Trumpet (KDS) monitors all with the same problem. Horizontal size adjustment has no effect. The display is pincushioned and too wide. The adjustment pot and wiring seems O.K but it has no effect on the display. Where can I get more online information on pincushion circuitry?One commonly-used circuit for controlling both horizontal width and pincushion (also called "East/West" or "E/W correction") is described in Sam Goldwasser's article On-Line at http//plop.phys.cwru.edu/repairfaq/REPAIR/F_deflfaq.html.  Failures in this type of circuit can give a too-wide and pincushioned display. QUESTION NO. P427-2:  Ultra VG-1520 monitor FCC IDk17vg-1520, dim and fuzzy picture.  I have exchanged the lm1203n and checked all the caps, resistors, transistor on the crt print with no luck.  When I first opened the cabinet, I could see that the shielding on the crt print did not have any connection to ground.Check the tube to make sure it is in good shape. Try to adjust the focus on the flyback. If the focus is at the end of the pot than it sounds like you have tube problems. Restore the tube for extended life. QUESTION NO. P520-3:  Mag DX700T monitor which is repeatedly blowing the HOT and R173. The board has been thorougly checked for dry joints. The fault occurs when the image size is increased to fill the screen. On resizing, the OSD loses sync and the picture folds back over itself on the left side before emitting a hissing sound and blowing the HOT. I have the schematic and some voltages are lower than expected. HOT collector pulses are 800v p-p instead of 1.2KV. The waveform is otherwise clean. I noticed that the HOT is running at a higher temperature than normal. I suspect either L103, T102 or the horizontal deflection yoke. Is there any means to find out if any of these is faulty? Are there any internet suppliers for the coils?Mag Technology (or Mag Innovision) is the primary source of coils, etc, for these units. The worldwide website is at www.magtechnology.com in North America, you can also try

website www.maginnovision.com.   For the DX700T, also check out Mag coil# LM*-751-401*0 LSE ; this coil may go bad when Q106 and R173 get blown. Also, capacitor C548 is a common problem.  You may wish to check with Mag Tech Support about C548, some units have had an upgrade of this cap with a 0.1 uF/500V ceramic cap (original cap is 1 uF).  In the US, Mag Tech support is at 714-751-2008, x895 ($25/10 min), and Mag parts can be had from Mag Innovision at (800)827-3998. QUESTION NO. P520-8:  Pacom mod CL15E monitor, picture is too wide. The panel controls have no effect towards correcting the problem.  I have checked all caps with an esr meter (all ok).If the FCC# ends in SM585F, check out capacitor C225 = 4.7uF/50V once more; ESR meters will not find shorted caps, or changes in capacitance value. QUESTION NO. P514-4:  Mag DX15Fe monitor in which the CRT was replaced.   Purity adjustment is OK but when converging the red and blue the red does not seem to be as high in the vertical sweep.  If you converge at the center the red is down from the top and up from the bottom.Answering my own question, I tried another CRT in case it was bad with no improvement. Changing the yoke solved the problem. It does test OK but marginally. I still do not know why it affected only the red gun though. QUESTION NO. P518-1:  Gateway 15" Vivitron monitor made by Sony and is equivalent to their 15" Vivitron. The color is not right in the lower right hand corner. The monitor worked for a while like this, but now it will not power up. Both LED's flash now.First, there are two Gateways that are 15" Sony chassis, which differ from each other. The unit is in shutdown (blinking LED's); the potential causes will depend on which exact chassis it is (indicated by the FCC# or Sony chassis#). But here is one point. The color problem sounds like a warp in the aperture grill in the CRT, requiring a new CRT, though it probably isn't the direct cause of the shutdown. But it may indicate the unit was roughly handled by the owner, and the Sony 15SF1 version (Sony SCC-H01A or SCC-H35A chassis types) can get cracks in the PC board traces, or broken pins on IC's, esp. near the center of the board, if rough handling causes the CRT to whack on the big heatsink there. Those cracks/broken pins are one of several causes of shutdowns in the 15SF1. There are also Gateways that are Sony 15SF2 chassis, which differ from the 15SF1. QUESTION NO. P518-6:  I need to identify a shorted diode D103 (1DQ065C) in a Mag Technology DX17F monitor (Manufactured July 1995).  I cannot cross reference it.IRF's 11DQ06 is a 1.1 Amp, 60 Volt Schottky rectifier ('5C' is a mfgr.'s code). Be aware that a 1 Amp Schottky only gives roughly 0.3V in the forward direction with a 1 mA test current, and so can seem shorted in some tests. If a replacement is still needed, Digikey (800-344-4539) lists it, as cat.# 11DQ06-ND, for $0.42 each. QUESTION NO. P415-8:  NEC XP17 monitor that powers up but immediately loses HV (I can see a picture very shortly and Green LED is OK).  All transistors around the FBT seems OK. Also vertical Def seems OK.I figured the problem out my self. It was the FBT that was defective. 

QUESTION NO. P514-9:  Two Mtek 17" monitors with same IC, a LH2426 with inputs damaged, giving a blurry image.  The LH2426 is a video amplifier made by National.  As an obsolete device, where can I get a substitute or a circuit to replace it?B&D Enterprises (800-458-6053) lists LH2426S for $42 each. QUESTION NO. P512-9:  I need a flyback for a Hitachi monitor. The part number on the flyback is KSF-61478.  I need a supplier for these parts.Try ASTI Magnetics 1-800-221-1828. QUESTION NO. P513-5:  Sony GDM-17e10 monitor that powers up and then goes into shutdown. The "power" and "power saving" LED's blink and the "cent" LED is on solid.Check FET Q511, HOT Q512; fuses PS500 & PS501; check all the electrolytic capacitors in the power supply section for leakiness or bad ESR. QUESTION NO. P513-3:  Compaq 461 monitor, fccid BR8SM-5514N (made by ADI Corp).  It comes on and works but has terrible linearity problems.  I found no controls (pots) on board for lin adjustments.  I did find an ext plug that goes to the memory daughter board.  Does this unit require an external module for programing?  What goes here?ADI chassis with that FCC# uses an ADI software/interface package for geometry alignments. ADI was selling that package for around $500 awhile back. QUESTION NO. P510-4:  Sony MultiscanHG 17 inch monitor CPD1604S that displays its image as trapezoid a shape.  Any adjustment I make only lasts until power off and shifts the narrow part from top to bottom.Go to the DA board, Sony# A-1346-069-A. If you can find one at a Sony distributor (they are discontinued), you might just replace the board. Otherwise, check all the SMD caps for leaking or high ESR, chances are there are several bad ones that need replacing. Esp.  check C328 and C334, also IC303 = TEA2031A. Clean the board well of any leaked electrolyte, repair any damaged PC traces, and run wires through any damaged through-hole connectors underneath these caps. Readjust RV309. QUESTION NO. P510-5:  GDM-20SE1 Monitor was dead. Q511 and Q512 were shoted. R470 was burnt. I replaced both Q's and R470 with a 1K (I think this was the right value).  I also found ps501 open and replaced it. Everything else checked ok. Powered up at 640 X 480 and ran for a few minutes. I changed to a higher res and heard a screech and lost power. It took out ps501 again and found Q511 shorted again.  On the PCB D504(Zener) is missing??, and C511 is a diode instead. (which seems to check good.) I also found R638 in the PS to be burnt a little, but not open. ( looks like .o47ohms) Q512 still looks ok. What is the value of diode in the C511 positsion?  Also the replacement Q511 was a TO-220ab so I had to use a mica insulator.The diodes off the gate of the FET Q511 are for gate protection. When a zener is used at location D504, generally 13V, this protects against gate overvoltage.   Some chassis, like yours, have a different diode, protecting against gate voltage reversal, and is either a germanium diode (like 1N132), or a Schottky type, which is chosen for its low forward voltage. R638 = 0.47 ohm/0.5W/ fusible.  With this model, check all the electrolytic caps in the power supply for leakiness or bad ESR; if bad, they can overwork and blow that circuit.  Also, Sony had a bulletin recommending that the spark gap be replaced with a 300

Volt unit.  Perhaps also see if D824, D825 are leaky under load. QUESTION NO. P512-3:  Hewlett Packard D2807A 17" Ergo Ultra VGA Monitor.  Kicks on for split second.  High voltage starts, then seems to go into shutdown or power save mode.  Most parts seen to be fine.  HP NOT helpful at all.Does the FCC# start with ACJ? If so, this "HP" is actually a Matsushita (Panasonic).  Their units are known for cracked PC traces, due to poor board design, so start looking for these. A common site is near where screws fasten down the board, but look the board over top to bottom. QUESTION NO. P511-8:  Dell p1728u monitor. The monitor powers up but there is no display.  The contrast and brightness leds are flashing on and off.   I have changed ic 902 already.  Also the neck is lit up which appears that there is high voltage.I think you will find that this "Dell" monitor is actually a Mitsubishi chassis.  This Mitsubishi's video cable does not use the standard VGA pinout, and using a standard VGA cable will not give any video.  Get the customer to bring in their video cable for this monitor.  If you have to make your own, the pins going into the monitor are pin#2 = red; #3= Red ground; #4 = green; #5 = green ground; #6 = blue ground; #8 = vert. sync.; #9 = horiz. sync.; #10 = blue; pins# 1,7, and 11-15 are no connection. QUESTION NO. P49-5:  Acer 7176I 17" monitor with Q311 (2SC4542) shorted. R338 burned open and R379 badly charred as well as R344 which tried to reflow solder itself.  I need the values of these resistors. Land pattern around R338 also badly charred and damaged but looks repairable.  I would guess that Q311 caused all the damage.The values for R338=10 Ohm;0,5Wt R379=18K;0,25Wt R344=82 Ohm;3Wt.   Most of them connected to +12V circuit. QUESTION NO. P56-8:  Dell ultra scan 17tx monitor, shuts down after about 2 seconds,and the amber LED flashes.  No horizontal startup.  I checked the H trans. and related components, all check O.K. The 5-volt stand-by voltage remains after shut-down,but all other voltages come up about half-way then shut-down.   Checked continuity on video cable, also checked Q417,420.This "Dell" is probably has a Sony FCC#. If so, a common failure part in those is R613 = 390K (if value bad, replace with 0.5W rating, also replace R612 & C600).  Check all "PS" type fuses (PS401, PS402, etc, around 8 total) and R638 for open; check IC401 = LM339 type, & IC403 = LM324 type; also check diodes D441 through D446. Check if VR401 is set for ~28KV. Sometimes the Eeprom goes bad in this Sony. QUESTION NO. P56-6:  Dell D1726S-HS monitor.  I need a hibrid ic location on pcb is HIC 401, on the part you can read this HS17 IEKS.  Who is selling these parts?If you check the FCC#, you will likely find that your "Dell" monitor is actually made by Samsung. If so, try getting this HIC from a Samsung supplier. In the US, for Samsung parts, you can try Herman's Electronics (800-938-4376) or J&J International (800-627-4368) on the east coast; Amcotron (800-344-3882) on the west coast; or maybe Samsung itself (800-726-7864). QUESTION NO. P46-2:  Sun monitor FCC # AK8GDM500PS, the green gun not

functioning.  I narrowed down the problem to the PCB directly behind the CRT labled "A" (sony part # 1-667-235-14).  I have traced the PCB traces back from the CRT to a chip labeled Hitachi FA4111 which is heatsinked directly to the metal chassis surrounding the monitor.  I suspect that the problem may lie here.  What does this chip do, and am I on the right track?Yes, replace the IC. QUESTION NO. P47-9:  Old Sony CVM-1225 color monitor.  The unit has about a 3-4" band on the left side of the raster that is significantly darker than the right side. The width of the band changes and the edge of the band is a moving ripple.  The problem occurs with B&W as well as color signals.  The output of the video amps seems to be OK.  24KV is OK.  Many other voltages are lower than called out on the schematic.Start replacing power supply caps.  An ESR meter would be helpfull finding the bad one. QUESTION NO. P428-1:  CTX 1565D monitor.  Apparently the user had the monitor  in use  face-down for an hour. The next day, when turning the monitor on, it was dim for 1/2 hour and then went back to normal intensity.  After shutting it off for a few hours and turning it back it was dim again and did not return to normal intensity.Check for a bad cap in the filliment voltage circut.  Or maybe bad conections.Resolder CRT socket to videoboard- the most common problem for 1565D. QUESTION NO. P414-9:  TVM md14IIIs2(lr) monitor.  It has shrunk horizontally and it is out of focus.Check horizontal transformer and check focus voltage it mybe good to check the yoke windings. QUESTION NO. P414-7:  HP A4033A monitor. The high voltage comes up when power is applied, but immediately after the monitor enters power saving mode. The power save light and power light blinks while the CENT light remains solid. No other LED's are on.  The component failures suggested in the answer for question P210-1 has been checked and found OK.This may be a failure in the horiz. deflection circuit, which is a separate circuit from the HV circuit. If you have already checked those parts indicated in P210-1, and also all the "PS" type fuses everywhere, then check the horizontal yoke transistor Q512, and the associated caps, rectifiers, etc. in the deflection circuit, and the FET circuitry regulating B+ and pin correction for the deflection circuit.   Also check ALL the electrolytic caps in the power supply, these chassis often turn out to have very many bad/marginal caps; for sure, check C611, C612. QUESTION NO. P428-3:  CTX 2085 monitor with no screen brightness.  The control pot does not work at all.  Pot is good, contrast works but no brightness.  Q401 (BF483) should measure -14v at collector but is measuring -156v.  Replaced transistor but still have same problem.  As a result G1 supply to negative.Check for lack of power to convergence output devices, such as open fuses and or fuse resistors. Also check for dry solder connections. As old as this set is you may also want to check any electrolytic capacitors in the convergence and supply circuits. 

QUESTION NO. P429-5:  CTX1765cd monitor, FCB DBL1765cd.   Screen is too dark, otherwise all OK.  "Screen" pot on fbt has no effect at all. Any other G2 or RGB adjustments?The screen pot will not work, because RGB & brightness settings are controlled digitally through an RS232 port. If you do not have the CTX software/hardware setup, a possible workaround is to cut the G2 line from the CRT bd, and insert a high-value (1 Mohm or so) resistor in line with R419 = 3.3 Mohm, to increase the total resistance. QUESTION NO. P421-5:  Optiquest 4000DS 17" monitor, does not have High voltage. Power supply voltages are OK per printing on board. Led lites indicating a vga signal present. The wave trace at base of HOT is not a good sawtooth signal.You should not expect a sawtooth at the base of a HOT.  Drive to B of HOT looks more like a rectangular with negative spikes on falling edge__ ___ .... hilevel ~+0.7V!____! !__ .. lolevel ~-2V! ! ! ! <-- 1st neg. spike below -5VIf signal to base of hot is other than rectangular waveform check drive (which is often done by a transformer - check the signal on its primary - it is rectangular again). If drive to hot (as shown above) is present scope C of hot.- ATTENTION ! Make sure your scope can handle >1200volts peak.  You should see needle like pulses starting at falling edge of hot-B drive.  If no trace there or scope not able to safely display 1200Vpeak, check the DC voltage at the collector print with HOT DISMOUNTED. Maybe the supply voltage (+b) to or through the flyback is missing.  If so and you find a burned fuse or fusible resistor in the supply path, check HOT for CE shorted. QUESTION NO. P331-7:  Three Samtron monitors, horz o/p (Q306) last for 2 min then over heats and shorts.When defection yoke is unplugged, Q306 does not over heat. I have all ready swamped the following parts from a good monitor:  FBT, defection yoke, all coils, and caps in defection circuit, H.D. xfromer, SPCTxformer.   When yoke is plugged back in, right side of screen is not filled and linearity and pincushion is very bad.Since you did most everything, all that is left would be to check pincusion output transistor/ic and adjacent coil/caps towards deflection.  Check damper diodes (if external) from c of HOT to GND. And besides caps and coils recheck diode(s) and low resistance/high wattage resistors in horiz linearity control (in series with yoke).  Are you sure the applied horiz. scan rate is not too high since I understand you have the same error on three sets? QUESTION NO. P427-7:  Sony cpt-17sf2.  c5023cs integral chip dead.  Is there an analogue and what are the characteristics?UPC5023CS is a customized IC, configurable by its maker (NEC) to the customer's specifications, so there is no alternative.  Even another UPC5023 IC from another application might be configured differently inside. QUESTION NO. P427-9:  Radius 0461 monitor Intelli color display 20e.  The fault is that the EHT comes up for a second or so and then dies.This Sony chassis is probably in shutdown, esp. if there are two LED's are blinking to

indicate this (another LED may be on solidly, to indicate the type of shutdown).  In general, given no specifics, check ALL microfuses (marked "PS"-something) for open, check FET Q511 and HOT Q512; rectifiers D504, D824, D825; IC404 and IC801; resistors R638, R851, R868; capacitor C822. Also check ALL electrolytic capacitors in the power supply. The flyback transformer (LOPT) can also go bad. QUESTION NO. P427-3:  Six Orchestra (KDS) Trumpet Monitors.   All have color smearing to the right of very dark or very light colors.  Two of these monitors also have pincushion/horizontall adjustment problems.Replace the six 1 uF caps (three bipolar, three high voltage) on the CRT board, these are a known cause of smearing. The front panel adjustment pots on the units with manual controls (H.size, H.width, H.phase, etc) are low-quality, so replacing these may solve the horizontal adjust problems. Sometimes there is a faulty signal cable (try wiggling it). QUESTION NO. P414-4:  Philip fsr871cv which is the same as Digital PCXAVF4 or Compaq 480/480p/481 monitor.  When doing power up diagnostic it first shows " H/V sync off" and then " High voltage failure" then the unit shuts down.A bad flyback unit generally causes this type of HV shutdown in these models.  Sometimes a bad focus assembly block can also, if you see focus or brightness problems occurring on the display before it shuts down. QUESTION NO. P47-7:  Mag DX1795.  With power, green LED comes on and then a click with no high voltage. I check the HOT and it is ok.  No visible cracks or cold soder joints.If there is no horizontal drive from TDA9103 IC to the HOT, the TDA9103 may be bad.  Also check if there are problems regulating the 12 Volt line from the power supply. QUESTION NO. P421-7:  Premio h566 15" monitor.  Works fine until it warms up. At first it just gave the hour glass effect, now it is just a shrunk picture (about one fourth of the screen and rolling fast).  Turn off and let it cool down for 15 minutes, and it is good to go for another hour or so. I used cool spray on Vertical and horizontal areas, with no noticeable effect.Replace the 42-pin PSDIP IC, TDA9103.  QUESTION NO. P420-2:  What is a transistor bearing markings FS14SM?  It is used in Acer computer monitor 15".FS14SM is a Mitsubishi FET, rated for 14 Amps, in a TO3P case.   For more on Mitsubishi FET marking codes, see answer P226-5 on the VCR Repairs page. QUESTION NO. P419-8:  Six ADI SM-5514a monitors that all display a green led and will not do anything else. I checked the hot and that is ok.  Could it be the Microprocessor chip that is on a small daughter board?The Zilog processor on the standup logic board is a common problem in this chassis for this symptom. Get its complete number and get a replacement from a supplier like LJ Enterprises (800-627-8755) or CCS (800-356-1227). IF the supplier wants to supply a Zilog with a different number, BE SURE they include ANY board modification instructions required to make it work in yours! ADI (800-228-0530) can also provide entire

replacement boards. Note, the signal from the Zilog routes to the drive circuit through some digital-switch transistors; these are usually OK, but they test out differently from standard transistors. QUESTION NO. P325-7:  Four Sony GDM-2038 monitors all doing the same thing. They shift to the right and when first turned on, they are in a horizontal roll.  After the monitor is on for 15 to 20 minutes it stops rolling and is fine, until after being on for long peroids of time (couple of days).You have bad caps in the sync circuit. QUESTION NO. P322-6:  Gateway (Mag) 1572FS monitor that has a series of horizontal lines that appear to go from bottom to top in "waves".   Is there a manufacture upgrade? Problem occurs from cold start. Before, only when warmed up.Check for bad caps in the vertical circuit. QUESTION NO. P319-2:  Two AcerView 7176IE monitors that exhibit video smear (a ghost effect on text characters and icons).  For example when when working with text documents the characters have a green tint and a light grey shadow to the right of the characters.You need to readjust the crt beam centering magnets. QUESTION NO. P318-10:  Sony CPD-17SF2 monitor, dead.   Replaced hot, now powers up, but shuts down with power+saving leds flashing, size led constant.You have a shorted fet at the input to the flyback. QUESTION NO. P49-9:  I have a lot of CRT (different make and size-14" and 15") which have same problem- focus can not be adjusted properly and picture size-horizontal and vertical changing with focus adjustment. RGB guns emission is perfect.  Most of CRTs are pretty new.You are encountering power regulation problems. Your B+ should remain constant when adjusting focus or screen.  It is also possible you have a bunch of bad transformers.Get the High Frequency Generator model BD-10ASV (or another one- this is for 230V AC)made by ELECTRO-TECHNIC PRODUCTS, INC. (the address 4642 North Ravenswood, Chicago, IL 60640). It seems your problem is dirty CRT inside. Before using this generator for CRT focus cleaning connect CRT's Anode to ground- make a connection tool from old one FBT. Usually helps. QUESTION NO. P49-3:  CTX 6488ES on power up there is only a steady white horizontal line in the middle of the screen.Troubleshoot and repair the Vertical circuit. QUESTION NO. P413-2:  Apple Multiple Scan 15 m/n 2978. What is SG305 on the video board?  It glows brightly, while the other Sg#'s just flicker.What you are describing is a spark gap.  Some companies use neon bulbs for this.  It is indicating that the crt is shorted on that gun. QUESTION NO. P415-9:  Compaq 151FS monitor, changes the color after 10 minutes

from white to red. If the housing is open the problem is fixed. I have changed the power semiconductor of red-line, it was not helpful.You probably have a bad processor ic and maybe a few caps. QUESTION NO. P415-1:  Gateway 2000 CS1776LE monitor.  Several parts related to Hivoltage are gone.  Q117 D799, Q116 IRF740, and Q109 C4747 (power out put high voltage) are shorted and C525 1/450v, C908 1/450v, C123 1/50v,and C123 1.5j are dried; ( Tested by ESR Meter).You also need to replace C120 1uf/50v and the part that caused it all "L105".When any of these parts dies, it takes out many others; all need to be replaced simultaneously, or the remaining bad parts will then kill the replacement parts.   Besides replacing all the parts mentioned, you also should replace tall coil L105, C120 = 1uF; also R181 = 120K if its value changed. Since Q116 was shorted, also check R177 = 1 ohm and D116 = 30DF6 (on tall heatsink, NTE580 sub). This is a Mag chassis, L105 is p/n# T*I-281-103-UO; get it from Mag Innovision, or from suppliers like LJ Enterprises, 800- 627-8755, or NEI, 888-634-7278. On rare occasions, the CRT socket or yoke connectors are burnt inside, may be worth inspecting. QUESTION NO. P416-10:  Digital Philips FSR871CV.  At the start the display is good, after a minute or so, the display becomes lighter and lighter and the desktop vanish.You may have a bad ground connection on the IHVT or it itself may be bad.The screen/focus blocks are a problem in this model. There are a few different versions; which version depends on which exact CRT is installed. If replacing it, you need the entire number off the one in your unit. In the US, LJ Enterprises, 800-627-8755, and MI Technologies, 937-335-4560, have carried them. For Europe, try ICHE in the UK, Phone, 044 (0) 115 932 0152; email, tony@iche.com. QUESTION NO. P416-7:  Dell D1025HE (FCC IEY447S). The height of the picture is too small (vertical), top is appr. at 50%.  Perhaps this is a software problem? Can I give a general reset in some way? (The factory defaults menu option does not help.)You need to troubleshoot the vertical circuit. QUESTION NO. P416-6:  What is the value of the hot on a Mag dx17f?Your transistor is a 2sc4747 VCEO=800V VCBO=1.5KV AMPS=10, you can also use a BU2525AFDepending on date of manufacture, Q109 is 2SC4747 (early) or 2SC5048 (later on).   The DX17F chassis sold as Micron monitors sometimes use 2SC5129 as well. These transistors are fairly interchangeable, 10 to 12 Amp HOT's. QUESTION NO. P329-6:  Sony 15SF2 that immediately gets very bright and out of focus and then shuts down.  I replaced the Flyback with no change.   R494 measures OK at 680k.The problem was a bad LM1207N on the CRT Socket Board! QUESTION NO. P412-1:  Hyundai HN-4850 monitor, FCC CKLHN-4850.   C515 (22u@50v 85c) blown and R526 (47ohm 0.25W) burned.  I replaced those and powered up unit with a variac slowly and C515 smoked again.  I found 70V on C515.   I subsequently found D581 (labeled T NH5) shorted.  It is in series with D582 (labeled T 3JU).  These

appear to be damper across the yoke.  The center connection diode junction goes pincushion circuit, I think ie to a TDA4950.  The diodes I cannot find in NTE or ECG for a specification guess.  Any other parts that may be blown that I have over looked so far?"T NH5" and "T 3JU" are Toshiba rectifiers, but Toshiba often uses markings that are not precisely the rectifier's part number. The "T" means Toshiba, "NH5" is rectifier 0.5NH45, rated 1000 V., 0.5 Amp, Trr < 200 nsec; and "3JU" is rectifier 3JU41, rated 600 V., 3 Amp, Trr < 100nsec. You might try subbing either NTE575 or NTE558 for the 0.5NH45, and NTE577 or HER506 for the 3JU41. QUESTION NO. P412-2:  IBM  6543-305 (G50) monitor, dead.   After replacing LM393 in power supply, the monitor works, but the bright control key does not.  The other control keys are working.Check R424, near the flyback, for value or open. If R424 is OK, see if that fragile ribbon cable assembly going to the user controls has broken, and needs replacing. QUESTION NO. P323-3:  Apple 1710 monitor (which I understand is a Sony monitor in disguise) and found the horizontal output transistor is shot. We replaced it but it is still getting too hot and still having pincushion problems and a too narrow picture.Check QL2 (IRF9630), RL83 (10E), QL23 (MJW16012, I think).   Resolder the transistors mounted on every heatsink. and resolder the cap's and coils in the PSU.  Check pulses on QL2 (gate), if not there check QL1 (BC547) else replace IV11 (located on the video board LM392-SMD). QUESTION NO. P331-3:  Compaq 462 display monitor has failed with blown components:  Q401, Q402, Q403, Q404, Q405, Q82 (Hor OP), R412.  R412 has vaporised. Can you please tell me what value this is? Also Q404 is marked F423, I can not identify this device in all my data books, can you give me an equivelant device number. Also, can you tell me what value B+ is set to, and if anything is common to cause this domino effect.If the "F423" has a TO-92 case, it is probably BF423, a Philips high-voltage PNP transistor.  MCM (800-543-4330) & Union Electronic Distr.(800-648-6657; http//www.unionel.com) list it. For the other data, Compaq isn't likely to help, so check your FCC#. If it is FCC #BR8SM-1457, it is made by ADI, model# SM-1457, and you might try that model# to see if you can get that info from ADI tech-support, email, techsupport@adiusa.com. QUESTION NO. P46-7:  How do I remove the cover of a Dell D1025HE 17" monitor?  Who is the manufacturer?Like many other computer manufacturers (including Packard Bell, Compaq, Gateway, Apple, and more), Dell often uses the same model number for monitors that are different chassis, from different manufacturers.  So be aware that if you post a question for any of these, and did not include the FCC number, any answers you get just might be for the wrong monitor chassis!  To find out the real manufacturer, get the first three characters from the FCC number, and look up the manufacturer on the FCC website at  http//www.fcc.gov/oet/fccid/. QUESTION NO. P46-4:  Packard Bell 1020 monitor works OK in 640x480.  Video barely visible at 800x600 and above.  All modes work OK on Checker 12E but not on computer. 

Tried on two computers.Since you did not give the monitor's FCC number, I do not know which Packard Bell chassis you actually have, but on at least one of those models, the picture goes dim if run at too high a scan rate on the newer video cards.  Try setting your computer's video cards for the old IBM 8514's scan rate, and see if the problem goes away. QUESTION NO. P45-10:  IBM G70 monitor  6544--403.  I need a part # cross for Q872.  The part is marked FQ161 replacing to fix green screen.If Q872 has a TO-92 case, this is probably a Philips BFQ161, NPN video transistor, rated 19 Vceo, 0.5 Amp, 1 Watt, Ft  >1 GHz; there is no ideal cross for this device.  Arrow Electronics (800-833-3557) lists BFQ161 in its inventory, or you might try a Philips distributor, but the device is obsolescent. QUESTION NO. P45-8:  Acer 7154e monitor. Transistor K22161 and BU2520AF have died. What their analogues and characteristics?I think you actually meant K2161, which is Q317 in this unit, a Sanyo FET = 2SK2161, rated 200V, 9 Amp, Rds[on]<0.35 ohm, 25 W., insulated TO220 case. A sub is IRF630 with insulating hardware. BU2520AF is a Philips horiz. deflection transistor, rated 1500 Vcbo, 800 Vceo, 10 Amp, 45 Watt, Tstg = 4.5 usec typical, Tf = 0.35 usec typical, DC gain (0.1 Amp) = 13 typical; SOT199 case, no internal damper diode. This transistor is readily available and inexpensive (in North America, at least); I recommend using the original type, but if not, possible subs might be Hitachi's 2SC5207A or Sanyo's 2SD1887. One source for all these is B&D Enterprises (800-458-6053). In this model, I suggest you also replace ceramic cap C335 = 220pF/2KV for this symptom.The problem is also true for a HP monitor model D2825 (or ULTRA VGA 1024).  The transistor 2SK2161 is equal at IRF630 or IRFI630. QUESTION NO. P330-3:  Packard Bell 1412SL, burnt out resistor R454. I need the value of this resistor.R454 is a carbon film 1/4W 2K ohm +/- 1%. QUESTION NO. P329-1:  Packard Bell 1412SL monitor FCC# BJMCM14UP with an open D814. (Looks like it is in the power supply section).  What is the problem and where can I get parts?D814 = UG2D, an ultrafast (Trr < 25nsec) rectifier, rated 200V, 2 Amp. If your supplier does not have this rectifier, some possible subs are SF24, SF25, or SF26 superfasts (all 2 Amp, rated at 200V, 300V, or 400V). Mouser (800-346-6873) lists those as cat.# 583-SF24, 583-SF25, or 583-SF26, all <$1 ea. Or NTE/ECG576 might be used, if you drill open the solder pads a bit wider. QUESTION NO. P42-5:  Gateway 2000, Model CS1572FS has Horz. shadows much like mouse cursors trails but they do not go away.  They are very noticable on icons and trail to the right of all open Window Boxes.  All else works fine.Gateway used "1572FS" for a couple of different chassis (different FCC#).  Smearing to the right is relatively common, and can be either the CRT being bad, or problems on the CRT board. If the smear to the right is white, not colored, this favors a bad CRT.  The units with Toshiba CRT's are generally bad CRT's, units with Hitachi CRT's are more likely to be

smeary from bad CRT boards.  In those, check the CRT boards for bad caps, transistors/ video amp IC, zeners, etc. In those chassis with R331, a 91K resistor in the power supply section, this resistor needs checking, because it can cause the CRT to die (and other problems) if its value is bad. QUESTION NO. P330-10:  Hyundai Model HCM-402c with loss of vertical hold.  Replaced vertical deflection circuit ic, checked all capacitors and resistors with no change of condition.  Everything else seems OK.Can you check the signal cable? QUESTION NO. P331-9:  Acer 7154e 15" monitor. Transistor K2161 is dead. I cannot find it, what is analog and its characteristic?K2161 is a Sanyo 2SK2161 FET, its characteristics are 200 Volt, 9 Amp, 25 Watt, Rds[on] <0.35 ohm at 4.5 Amps, in an insulated TO220 case. B & D Enterprises (800-458-6053) lists 2SK2161 for $2.90. Or use IRF630 with insulating hardware.  For this fault, better also check C335, coil L304 (2 mH), D316 & D317 as well. QUESTION NO. P325-4:  I need a supplier for a chip ux051b0102 for an ADI SGVA monitor.This chip is actually UX051B010Z, so your supplier may not have recognized the incorrect number. In the US, places like CCS/EDI (800-426-6423), LJ Enterprises (800-627-8755), or NEI (888-634-7278) often have preprogrammed uProcessors.   If their price is very high, you might see if a whole new CPU card from ADI (800-228-0530) is available. QUESTION NO. P325-2:  CTX-1565D. Picture is very dim and has some smearing of text in all video modes. It appears that the brightness and contrast controls are working correctly. The CRT is made by Samsung and has the part # M36KUK35X15. Is it probable that the CRT is bad?Dim, smeary picture in a Samsung CRT is very commonly a bad CRT. But before condemning it, check if the filaments have sufficient voltage, or if there is much AC ripple in the filament supply due to a bad filter cap.  QUESTION NO. P325-9:  AOC CM-335 monitor.  Line output transistor (Q405) replaced 6 months ago with C4769 (2SC4769??) has failed again.  Is this the correct component for this monitor?  Also is there any known historical reason for early failure of this component?The AOC CM-335 has several different chassis versions, with differing FCC numbers.  In FCC#ARSCM3352, the H.O.T. is Q405 and that one is 2SC4769. This H.O.T. may fail due to a bad horiz. drive cap C417 = 47uF/50V, next to T401, the drive transformer. QUESTION NO. P319-3:  TTX model TTX-3500 monitor. I need to know the following parts in the power supply which were missing:  ZD 4,. D 15 and D 18. The unit was a mess, iIt had both p/s problems and a blown HOT.ZD4 is a 1N759A (12v),D15 is a UF5402 and D18 is a UF5408.  Just finished replacing these parts on a TTX 3500 . Check both Q612 and Q603.  Both were shorted in my unit.  Also, R645 (2.2 ohm) was open. QUESTION NO. P317-6:  Siemens Nixdorf Scenic Monitor PM 150 G5 S26361 K408

F516, FCC ID JVP71561S.  I need a supplier for transistor TOP214AY1.   I have tried most companys in the UK.First, "TOP214AY1" (actually TOP214YAI) is not a transistor, it is a specialized power IC, that combines a PWM regulator with a power MOSFET, inside it. It is made by Power Integrations Inc, but since you are in the UK, I suggest you contact Sequoia Tekelec, Ltd., www.sequoia.co.uk, address Tekelec House, Back Lane, Spencers Wood, Reading, BERKS, RG7 1PW. United Kingdom.  Telephone 0118 925 8000 Fax 0118 925 8020 Technical Help & Data Line 0118 925 8090 Technical Fax 0118 925 8060.   You can read specifications, and a schematic using this IC, at this Sequoia URL http//www.sequoia.co.uk/Products/PI/top200.htm. QUESTION NO. P317-7:  NEC monitor JC-1733VMA which displays a green LED but no video. Items that checked good were heater, HV (stays on) and power supply output voltages.Check the CRT board for a high-ohm resistor, I think R906, 1.5 Mohm, that goes bad. QUESTION NO. P310-1:  ASTVision 7N (KD-1711) with R916 & R907 near the flyback burned beyond recognition.  I need their values.KD1710, a similar model, has R907 = 10K/0.5W; R916 = 100K. QUESTION NO. P316-3:  DX15FG Mag monitor, width too wide - unadjustable.  CPU is changing level while pushing width button.  Caps tested ok ESR. transistors in horizontal section statically ok.First check caps C105 or C106, 0.0068 uF, near flyback. If OK, is the VGA B+ voltage regulating at about 71 VDC and about 1100 Vp-p?  If the B+ regulates OK, try tracing the width circuit; you may have a bad part or bad solder joint on that circuit.  By "cpu", do you mean the TDA9103? This IC is a known problem, but if your IC's output is OK, as you say, then start tracing the width signal elsewhere. Try to vary the signal, using the + and - buttons, and check if it varies off pin 7 of IC102, then Q203, then C108, L106, L105, and on to the yoke connections. Note by the time the signal is reaching the coils and yoke, you may have Vp-p values of hundreds of volts. QUESTION NO. P33-5:   Je travaille sur un Sony 17" CPD-17SF2.Quand on le met en marche la THT demare la trame aussi,puis plus rien.  Les tensions sur le secondaire de l'alim sont présentent.Deux LED orange et verte clignotte et la led orange du réglage de géométrie reste eclairé en permanence.  Quelqu'un pourrait-il m'aider.Check ta haute tension (frequence). QUESTION NO. P29-2:  ADI 5V model #LM1764 dead with good fuse.   I cannot find much on it and Iam stumped.Try checking H.O.T and if tests good check power supply.  You did not say if there was any led flashing so this is all I can give on this. QUESTION NO. P311-10:  I need a source for parts for a Cushman ce-2b service monitor.  The parts I am looking for are HPA0136 Snap Diodes ( or Step recovery diodes ).  I need at least one diode to repair this unit.Try RF Parts in San Mateo California. They carry a lot of unique RF parts.  Phone number

1-800-737-2787 for parts and 760-744-0750 for technical help. QUESTION NO. P225-4:  Have a few NEC XV17 model JC 1734VMA monitors, FCC #A3DJC-1734VMA.  Two units had poor focus that could not be adjusted with fbt pots.  Replaced cracked fbt with good units, and now cannot properly adjust focus.  Is there a secondary adjustment/part replacement to calibrate for new fbt?If you can go from bloom to bloom you have a bad crt.  If it is almost focused at one end, then you need to readjust the high-voltage regulator. QUESTION NO. P34-4:  NEC 3D monitor that when turned on just has a white line across the center of the picture tube.Check for vcc at pin 1, 12volts. and for b+ at pin 7, 24volts.   You may need to replace the LA7835 ic. QUESTION NO. P310-10:  Three Apple 12" RGB color monitor model No1296 with the same fault. The horizontal collapses about half an hour after it is turned on and then collapses almost staight away after it is turned back on.You probably need to resolder the yoke plug. This is a common problem with this unit. QUESTION NO. P310-8:  Acerview 7134T (FCC ID #JVP7134T).  No light on the power LED, the monitor is completely dead.  Checked fuse, ok. Checked filter caps around power supply with an ESR meter, caps ok.Check the H.O.T.  You can pull it and see if the S.M.P.S. fires up. QUESTION NO. P310-7:  Maxtech XT-4800 with no blue drive.  I changed the MM1203N checked all caps and resistors on yoke board without change.  I believe this monitor is made by Samsung.It is not the yoke board, it is the crt drive pcb. You can compare red and blue.  Red in is pin 4, Blue in is pin 9. Red out is pin 25, Blue out is pin 16.   Have you checked the video cable? QUESTION NO. P218-6:  TTX 3500 monitor with no horizontal sweep. Displays only a thin vertical line.Replace the vertical output I.C. and/or troubleshoot the vertical circut and related supplys. QUESTION NO. P310-3:  Logix LG-143snie monitor with a faulty ic902 located on a small circuit bd used to power up the monitor when a video signal is applied.   I need a replacement number for this component.  Its only markings are a509 k12no 6l made by SGS Thompson Malaysia.That "IC" is a logic-level FET, SGS# STK12N06L. You did not say if yours is an SMD type, or a thru-hole FET (it comes both ways). If you cannot find it, I suggest getting one of SGS's STD12N06L-1 (thru-hole), or STD12N06L (SMD), for example, from Mouser (800-346-6873, cat# 511-STD12N06L1 or 511-STD12N06L). If it is the thru-hole FET, it would be good to attach a small heatsink, if there is not one present already.  These STD FET's are similar to the STK type, but the packaging is a bit different. QUESTION NO. P210-4:  I need the value of a capacitator C322 in an AST SVGA-LR14.

The component C322 has the markings "6n2 J 1600V Philips". QUESTION NO. P223-3:  LEO-1423A monitor from First International Computer, Taiwan. The screen has display but it is very dark (dim) even if brightness and contrast is set to full.Check crt if Samsung that is 34kun at the begining of number these crts are famous for going bad. And you can not rejuvenate these crts.  If not Samsung tube, check all voltages on crt board to make sure they are correct.  If correct, then crt is worn out and maybe you can have it tested and try to restore it with a crt tester-restorer. QUESTION NO. P215-8:  Daytek 14" model DT14SNI no vertical deflection, only horizontal line in center of screen. Replaced vertical IC as well as repaired numerous bad solder connections. Problem still the same.I would first check all caps in the vertical section.  Heat can cause bad esr.  Replace bad caps with 105 degree caps.  Also check the yoke for possible short QUESTION NO. P226-7:  Samtron 428V+ monitor of which the horizontal size (top to bottom) is reduced. When I try to adjust the picture size, it does not go bigger than just a bit more than 3/4 of the screen and gets sort of flyback lines at the bottom part of the screen, almost like a foldover.  When I adjust the picture location, it does the same thing when I try to adjust the bottom part of the picture below 3/4 of the screen.The Samtron problem is the vertical defection ic it is a tda series inline ic. QUESTION NO. P127-7:  Aiwa CX-999U. The display is extremely dim. I do not have any of the specs and no voltages are marked. The florescent display, if it is like every other, should have ~3V AC from each side and ~(-25V) DC on each active pin of the display. The AC is there, but I am measuring 3~5V DC on the active pins. Is this common? If not, where does the display voltage come from and what should it be?Check -33v line one filter is open. QUESTION NO. P226-6:  AST 5L FCC# GKR562D that has blotches on the CRT.  Looks like a magnet was held next to it for too long.  Is it worth buying a manual degausser for this?Take a weller or equiv. soldering gun.  Turn it on, rotate and slide it up against the blotch on the tube face for 5 or 6 sec. (watch the hot tip).   Withdraw the gun leaving it on all the while.  When 2 or 3 ft. away, turn it off.  Done. QUESTION NO. P226-8:  Compaq model 620 monitor, fcc id BR8SM769. It has a good display, but when the display changes contrast level, horiz width changes, sometimes it will pull in a couple of inches. Looks like voltage regulation to me.Try replacing the high-voltage electrolytic cap just outside the flyback cage. That cap can give these symptoms when bad. If it is OK, then check the B+ regulation. QUESTION NO. P225-2:  IBM 6540-00N monitor. No screen, LED is on, have high voltage(25Kv), tube neck doesn't light up, 0v at heater. Capacitor between the two heater lines says 223Z on it, What value is this? (223pF?) The value is 0.022 uF. See the answer to question# P216-2, on the TV repairs answer page,

for the details on reading these capacitors. QUESTION NO. P218-7:  Acer 1772e monitor.  R239 is burned, I need the value.R239 = 0.5 ohm/0.5 Watt/ fusible. Also check Q311. QUESTION NO. P223-1:  NEC Multisync monitor model no. JC-1734VMA.   I need the value of Q541.Q541 = 2SC5047. Before replacing Q541, check if Q572 = P-FET (2SJ306 or 2SJ307) has gone leaky or shorted, or else high B+ voltage may blow your new HOT as well.   Also be sure R538 on main board is not accidentally touching and shorting to the shield.  Parts available from MCM (800-543-4330), or B&D Enterprises (800-458-6053).Q541 is marked C5047. QUESTION NO. P222-10:  Several Magitronic computer monitors. Model number is C-SV1448. Fcc ID# is H41CM14005.  Where can I buy L802 at. These Coils go bad causing the HOT to blow.Your FCC# actually starts with H4I, not H41, which makes Lite-On Technology the manufacturer. In the US, you can try Lite-On at 408-946-4873 or 408-946-1751, or else try L.J. Enterprises, 800-627-8755, another source for Lite-On parts. QUESTION NO. P29-4:  What is the value of Q427 on the main board of an AOC model 7Hlr?Answering my own question, I finally found a service manual for the AOC 7Hlr monitor. Q427 is a BU2525AF. QUESTION NO. P216-10:  NEC 4FG 15" monitor with a focus problem. I can adjust the focus but it will change and need to be readjusted. It constantly changes.You need to replace the flyback, they are known for this. QUESTION NO. P119-9:  MAG DX15F monitor Q502 bad, need value?Value of Q502 on DX15FG is 2SC-3198Y. QUESTION NO. P114-9:  Apple multiple scan 17 display model M2494 made by Sony.  Someone has removed the FET location number Q505 I need the generic number for it.Q505 = IRFI9630. QUESTION NO. P211-9:  Wen monitor Model JD144L which came in with the power supply "tripping".   I found that the HOT was faulty and replaced it with the original BU5208DF. Before powering up I checked the power supply output to the HOT and it was 81 or so volts - I assume that is correct, so connected it and I powered up and it blew again. I have checked every diode and capacitor around the flyback and I cannot come up with a thing. I am suspicious of the flyback, but I am unable to source one here to prove it.  Monitor flybacks in South Africa are scarce.Check for a shorted flyback drive F.E.T. QUESTION NO. P212-10:  Three Apple 12" RGB color monitors Model No M1296X.  When first turned on, everything works ok but after about half an hour the horizontal

collapses and the screen goes blank. When turned off then on again, the horizontal collapses very quickly. The problem would appear to be a common problem with the three.You have bad connections on the yoke plug.  Check the horizontal circuit in general and also check the video drive ic. QUESTION NO. P210-1:  HP 4033a monitor (fcc id# ak8gdm20e01) which was dead. I replaced two shorted transistors Q510 and Q 511. The units high voltage comes up for a second and the unit goes into shut down. The amber power save light and the green power light blink together. Everthing checks ok , I supect the fly back.On this Sony chassis, the blinking LED's indicate a shutdown, but there are several causes of this. It could have helped to indicate which LED's were on solid, as well as which are blinking, to narrow down the possibilities. Given that Q510 and Q511 were shorted, check these other common failure parts Sony small white fuses, PS500, PS501, PS800, etc. (SOC1000 or SOC1600 = 1 Amp or 1.6 Amp, can sub Picofuse types); C822; R868; D824, D825; IC404 = TL082 dual JFET opamp, IC801 = 4049B logic IC. Also test any diodes from gate to source off of FET Q511, these may be zeners (like D504, if present) for gate overvoltage protection and/or Schottky (or germanium) types, for voltage-reversal protection. QUESTION NO. P29-5:  Apple multiple scan 15 (model M2978) out of horisontal sync.  I have changed TDA9102 without success.Most likely, the problem is a cheap fix, replacing IC951 = 12 Volt regulator IC, if it is not outputting 12 V. correctly. If that is not the fix, check transistors as you trace from IC951, until you reach the pin on the TDA9102; if these are also good, try replacing hybrid  IC501 = HIC CQ465 (contact a Goldstar supplier for this). QUESTION NO. P114-4:  Compaq Qvision200 model 480. The unit comes up with a vertical sync out of range error then a high voltage failure. I have tried several scan rates up to 1280 by 1024 with he same errors. The vertical and horizontal pulses are getting to the yoke at the correct frequencies. Checking by means of schematics I appear to also be getting both horizonatal and vertical failures. The signal common to both of these is the blanking pulse which is about 4.4 volts peak to peak. The signal after a divider is only about 0.75 v p-p. What level signal should I see at this point ( the junction of R889 & R904)?   Q860 and Q861 have been changed with no improvement. The manufacturers of these monitors are at best unco-operative.Check L807. QUESTION NO. P113-9:  CTX vl500 with a loss of video and shutdown after 10 seconds.  This monitor came in with a busted connector on the video cable. A possible short in the video circuit?It is possible, but first make sure that you are getting Horz. and Vert. Sync into the unit.  Without them the set will not fire up. QUESTION NO. P18-1:  Gateway monitor, model YE0711-01. When I power it up, a relay begins to click on/off continuously. From time to time I was able to power it up by tapping on the circuit board, thinking that it was an intermittent problem. This process has now proved me wrong because I cannot get it to power up anymore and the relay continues to

click. I have read that another of these had a similar problem and it turned out to be the flyback. First recheck any resoldering that you did to make sure you did not bridge any connections.  If that fails, try the flyback.. Have you checked the H.O.T.? QUESTION NO. P25-1:  Packard Bell 1020 that went dead. It sounds as if it is in HV shut down. Repaired all broken solder joints and replaced two resistors. No LED activity on the front, just the tic tic sound.Cheched the H.O.T. it is the most common cause of the TIC TIC sound. QUESTION NO. P121-3:   DTK monitor TF-14NLG FCCIDBJMCM14UH.   When powering on, both ver. and hor. rasters appear for a split second, then screen goes black. If I vary the scan rate and B+ voltage, I can get a picture for about 5-10 seconds, then the protection circuitry kicks in and the screen goes black. Power LED goes from green to orange. It looks like there is a problem with the switching P/S. If the picture comes up, transistor Q809 becomes extremely hot. Tried swapping out several parts, but have no schematic on this model.Is the monitor hooked up to a pc when you power it up?  Many Data Train monitors require a signal on the input, if not they go into low power (no raster) within seconds of powering up. QUESTION NO. P16-1:  PROTON GM-1449 monitor that changes colors to blue but you can still see everything.  The blue takes over the display you can see the other colors but with the blue overpowering.  It seems to change on its own from blue to normal. I noticed that mouse movements and opening and closing programs does have an effect on the display from blue to normal.It sounds like you have bad connections on the video prosser ic QUESTION NO. P129-7:  IBM  9527 17P Monitor.  It looks like regulation trouble.When you turn on the monitor It is very dim.Turning up the screen control,causes a wide fluctuation in the screen size.  Almost invariably a cap in switched mode?  Closed architecture of course.  Cannot get any schematics from ICM,or IBM.It's time tp polish off those trouble shooting skills. Is the switch-mode voltage changing?  You may have a bad FET on the input to the flyback.   Of course you could have a bad flyback or even a shorted crt. QUESTION NO. P22-1:  KFC 14". I need a cross reference on photocoupler CQY 80NG.CQY80NG is a Telefunken (now TEMIC) phototransistor optoisolator, Vceo > 32V, with CTR >50% (90% typical). ECG3041 can be a cross for this. Other alternatives might be H11A1, CNY17-2, or 4N35. A "typical" 4N26, with a typical CTR = 100%, might also work, but the guaranteed CTR of 4N26 is only >20%.You can use an ECG3096 It is rated a little higher than the CQY80NG QUESTION NO. P21-7:  Arcus 17" monitor, model DB-1765 BA, FCC ID H79DB-1765. When powered on, no lights or picture, high-pitched whine, and D418 is emitting smoke from solder joint that is part of trace to pin #8 of flyback.   Resoldered, still smoking.Did you replace D418?  Also have you checked the circuit that D418 supplies?

Replace Horizontal Output Transistor (H.O.T.). Original H.O.T. made by Phillips, BU2520AF. Replace with NTE2354. QUESTION NO. P22-7:  Unbadged monitor Model Number SM584V manufactured 9/98.  It has digitally controlled settings apart from the brightness and contrast. The problem is the power supply was dead. Line-op transistor Q207 (2SC5129) was found to be short circuit. Unable to locate a replacement here in the UK, so fitted a BU2508AF. The monitor supply now comes up, then only kicks in for a few seconds then goes dead.  The set is fitted with a GoldStar tube, and there a lot of Goldstar chip inside and it was made in Korea.You probably have a shorted FET on the input to the flyback. QUESTION NO. P22-5:  Sony GDM-17E10 that has an intermittent vertical jitter. This problem occurs about 10 minutes after the monitor has warmed up. Using a freeze spray I have pinned down the problem to the small daughter board(A-1394-579E) that sits right under the CRT. What specific parts need to be replaced and where can I purchase them? The fastest way is to replace all of those little metal can surface mount caps.  They are available from Nationwide Electronics 1-888-634-7278. QUESTION NO. P113-10:  N.E.C. 4FG monitor has excessive brightness with retrace lines.Replace the flyback if your crt is not shorted. QUESTION NO. P127-5:  Radius IntelliColor Display 20 Monitor (Sony GDM-2039) MO# 0381 with intermittent focus problems and brightness changes. Hard to set perfect focus.Replace the Flyback. QUESTION NO. P22-3:  Samtron 50e monitor which has an arcing problem in the focus section in the neck pcb. Arcing is happening exactly in the sparkgap provided inside the crt neck connector. I replaced the same and also reduced focus voltage but problem persists. Problem remains even after removing the tube connection.If you have replaced the crt socket you may need to replace the flyback.  You may also have a broken connection an the ground of the flyback.Replace the crt socket as an assembly. Probably arcing inside the socket. QUESTION NO. P23-2:   CTX 17" Color Monitor mode1765D FCC IDDBL1765D manufactured July 96 by CHUNTEX ELECTRONIC (taiwan).  I need the monitor component chip/transistor part no.C4632C4632 is a 2SC4632 or a ECG2588 and is available from Dalbini 1-800-325-2264. QUESTION NO. P17-7:  Compaq Monitor model # 443 FCC # BR8SM-5515G-A ASSY. # 147254-002 made Oct 93.  The diplay will work for about 1 minute then dies. The high voltage falls off during this time. I think the trouble is in the protect circuit.  I took out the power transistor and the PS voltage did the same thing. Check the Hv Transformer for a short. QUESTION NO. P129-8:  AOC CM-336 14".  The monitor was dead.  I found one bad

diode 31-df and replaced it.  The monitor was good for only 2 hours.After that the same diode was bad.  I put a new one in, but I measured the current which was flowing through the diode,the current in one direction was 0.5A, but in the other it was 1A and it was raising constantly.A diode conducting current in both directions like that is no longer a diode, it is silicon slag. The "31DF" series devices are all rated 3 Amp, and Trr < 30 nsec, but you didn't give the number that follows the "31DF", which gives the voltage rating, in hundreds of volts.  Those currents did not exceed 3 Amps, so if you have used the same voltage 31DF rectifier, check if the reverse voltage is peaking  so high that the rectifier is breaking down. If you did not use an exact substitute, did your replacement 31DF have a voltage rating that was lower than the original?  Or did you substitute a different type rectifier, with a Trr that was too slow? QUESTION NO. P21-8:  I need the value of R486 for an Apple M1298 16" monitor FCC# BCGM1298.  Also would like to know the values of the divder network resistors(EY63,64,&65) in the flyback.  It appears to me that the resistance from the HV out of the flyback to ground is low.  It measures in the 1 meg range. The unit had no HV. I found PS502 & 504 blown and IC404 bad. It appears to me that the input to IC404 is too high.If there is no HV check SMD's IC404 (4558) & R486 (10k) located on the solder side of main bd back & center. If they are bad, flyback may be defective (very expensive). QUESTION NO. P128-5:  Two monitors in the shop (same chassis), a Packard Bell 8515svgl and an IBM 228-001 with similar problems.  The IBM has no vert. sync. The Packard Bell has a vertically jumpy picture. I suspect ic 804, GSMCA24G1.0 and ic802, GSM CA-24-1 on both. If so, where can I purchase them?The chassis and IC numbers are Goldstar, so see if one of these Goldstar suppliers can provide the parts Astro at (800)252-7788, Shine Electronics at (800)221-0404, or Goldstar themselves at (800)777-1192; (800)668-8776 in Canada. QUESTION NO. P126-2:  Maxtech XT-5800 15" VGA monitor that works well when in the boot up screen but after the Win95 logo appears, the screen is from the top and down about 4" and the video is not readable.Replace the TDA9103 IC, it has gone bad. QUESTION NO. P120-1:   I refer to question P717-13. I need to replace a degauss posistor SINCERA DGC3R18M on Siemens monitor MCM1404. Unable to find part specs or manufacturer phone/address on the WEB.  Here in Germany I can replace the part by Siemens Matsushita B59xx posistor. Do you know the posistor cold temp. value (18 ohms?)?Sincera is now Walsin Technology Corporation. You can download their catalog as a .EXE file from ftp//vmail.vitalic.com/pub/walsintech/ptcr.exe The catalog is in Microsoft Word 7.0 format, and has the specifications of the DGC3 posistors.  In Germany, Walsin products are distributed by dbTec Electronic Component Distribution GmbH; Erhardtstr, 15 D-80469 Munchen, Germany; Tel +49-89-20900180, Fax +49-89-20900181, E-mail dbTec@compuserver.com and also by ETS, Welferode Hassalweg 6 34576 Hamburg, Germany Tel +49-5685-521; Fax +49-5685-8281.

 QUESTION NO. P120-6:  Monitor Model EVOKD-1700V.  Flashing led when push the power.I have found that most if not all flashing power LEDs are usually caused by the power supply recycling. The most common cause is a short or shorted component on one of the power supply voltages. For example a shorted HOT will pull down the +80 - 150 volt line an  cause the power supply to recycle.  Other causes are bad caps in the filter network.Check the resistance from ground to each voltage.  Low voltage supplies run 40-100 ohms. Hi voltage is usually at least 1k or higher.Monitors whose FCC# begin with EVO are made by KDS. The KD-1700V model has a design flaw, and KDS (800-283-1311) sells a re-work kit for repairing this model.   Read more about this problem at http//www.mitechnologies.com/news.html, QUESTION NO. P118-7:  Packard Bell monitor, model PB 8528 SV, FCC #BJMCM1498T, with a missing T401. The service literature list the part as TLN 142. Any help with finding a source for the driver transformer?An FCC# starting with BJM indicates the chassis is made by Tatung, so try getting it from Tatung with that TLN-142 part number. Tatung Tech support is at 800-827-2850, or email tech@tatungusa.com. QUESTION NO. P119-7:  NEC Multisync 5D in for repair, model no. JC-2002VMA.  The problem is that there are parts missing. Q560 and D560 are gone along with their heat sink. I believe they are the HOT and damper.The information you need is contained in the answer to Question P129-4. QUESTION NO. P115-6:   Gateway monitor, model PMV 1448/1024 NI, FCC #IAWPMV1448. While trying to adjust the horizontal width, the core of L102 started to break apart. The number on top of the coil is LS*-30L-10L-E1 and the service literature list the part as a H-VD. Any help with finding a source for the coil and how I can correct my problem of insufficient width? The sides or pulled in by about an inch.When the FCC# begins with IAW, that is a Mag Innovision chassis, and that coil's part number looks like a Mag part#, so try ordering it from Mag-Innovision, 800-827-3998.Please note, when adjusting the size on this older unit, that PMV1448 was not intended to be a full-width monitor, so do not over-do the width adjustments, as there will be a black border around the display.  QUESTION NO. P115-5:   Mag DX700T FCC ID# IAWDX17T-II.   After replacing Q106, and R173, the unit was restored to operation.  About 20 minutes later, the unit shut down and Q106 was once again shorted. I also did the C548 upgrade with a .1 mfd 500v ceramic disc cap. Any clues as to why unit killed horizontal output?   Also, horizontal pulse has what appears to have a harmonic pulse which is about 15 percent of the amplitude of the fundimental pulse.Did coil L105 check OK? I beleive the DX700T coil's part number from MagInnovision, LM*-751-401*0 LSE, is different than for the DX17F model, but it may also get cooked. QUESTION NO. P114-3:  Compaq QVision 172 Model 451. FCCID IEY447E. Spares No. 143547-002. Resistors R195 & R205(values 215 ohm) smoked & a surface mount

transistor located on the back of the deflection board close to R191 on the top marked with a 3F is shorted out. What is its complete part number?Some manufacturers use '3F' as the marking code for the BC857B transistor, a SOT-23 PNP transistor similar electrically to the BC557B (TO-92 device). But marking codes for SMD devices are not standardized across the industry, so this is not a guarantee.  If it is that device, then pin#1 = base, pin#2 = emitter, and pin#3 (on opposite side) = collector. QUESTION NO. P16-8:  I need the characteristics for C4916 and his(its) analogue.Assuming it's an air core ceramic based condensor for a glueifuklen 9000, it is 10.34farad @ 22 volt.2SC4916 is a Toshiba horizontal deflection transistor, rated 1500 Vcbo, 7 Amp Ic, with an internal damper diode. MCM (800-543-4330) lists 2SC4916 in stock, but   possible substitutes might be Sanyo's 2SC4123 or Toshiba's 2SC5149. Any subs, of course, cannot be guaranteed to work for all possible chassis. QUESTION NO. P1231-10:  I need a cross reference for ic TLS1233N for Proview 14" monitor.TLS1233N is a Texas Instruments RGB preamp IC. Its pinout is different from other IC's for this function (like LM1203), and I do not know any cross. If it is a help, Arrow Semiconductor (800-777-2776) does list TLS1233N in its stock, $1.50 each. QUESTION NO. P1210-8:  CTX 1451 - dead.   I need the part number or cross for q101 which looks like k118.Part number is 2sk955, but see other answered questions for more information QUESTION NO. P1223-5:  Apple M2494, someone has removed the FET Q503.  I need to know what the generic part number is.Q503 has the following markings on it 1RF19630G 5X2X 9524. QUESTION NO. P127-3:  Sanyo ds20930 chassis which shuts down as soon as it is turned on.   I ran it a reduced voltage and it seems ok but the vertical size is only about 85% maximum.  How can I increase the vertical size?I have since found the potentiometer on the main board itself and have adjusted the vertical size acceptably.  Would be interested in knowing why it shuts down with ordinary 120 vac applied. QUESTION NO. P129-2:  Digital PCXBV-ZW with (2) resistors in the P.S. burned beyond recognition. R956 & R957 near the PS reg. STRS6718.R956 is 7500 ohm 1/4 watt, R957 is 100 ohm 1/4 watt. QUESTION NO. P1210-7:  Nec XE15 monitor that, after it warms up, it collapses vertically and the power light turns amber, then it comes back up for one second and does it again.  It continues with this cycle until turned off.  It sounds like the high voltage goes down also during this cycle.This sounds like a bad IC881 = TMP87CK42N chip, but these are expensive, so try to confirm first with freeze spray or heat before replacing.  NEI (888-634-7278) has had these, be sure to note the suffix code off the IC to get the correct version.

 QUESTION NO. P127-10:   Packard Bell Monitor Model 1402s FCC# h4icm14012.  Looking for a cross and replacing for FET sss6n60a and mov r802.The SSS6N60 is currently available as a MTP6N60E from LJ Enterprises at around $7.00 each in small quantities. Likely that they would have the MOV that you are loking for as well. 800-627-8755. QUESTION NO. P1210-4:   IBM G70 6644-433 monitor. Horizontal width jumps from normal full screen to full screen minus 1" on each side. Left most push buttton (\\ >.<) restores screen to full. This happens at approximately 5 to 10 minute intervals. I suspect that the microprocesser is the culprit, but would like another opinion before I spend the $40.I have seen two IBM G70 monitors with similar problems. The buttons seem to drift on their own. Cleaning the ribbon cable contacts on the mylar button strip fixed one but the other needed a new mylar button strip. To test this, set the controls and then disconnect the strip. The monitor stayed stable this time. One monitor had the horizontal problem and the other had a standby problem as well as the screen would lose blue over a few minutes (this one was fixed by cleaning the contacts). QUESTION NO. P128-4:  I have a Commodore 1901 monitor, but I do not have the pin out.Standard DIN plug numbered clockwise from notch, 1,4,2,5,3 when viewed from connector open end. 1 Luminence 2 Earth 3 Audio Out 4 Video Out 5Audio In.   Other than that, it may have a standard shape cga plug with standard {CBM} pin outs. QUESTION NO. P129-4:  NEC Multisync 5D monitor model no. JC-2002VMA. Two components are missing, Q560 and D560.  I need help identifying these two parts.Q560 is a HPA150R available from L.J. Enterprises, CCS, etc. D560 is not used when D561 & D562 are installed. They are RG2A2. These series diodes with their cathodes toward the collector of Q560 shunt Q560 to ground. To prevent your replacement Q560 from failing again, be sure to replace C541 (100uf @ 50v) & Q5P0 (2SK758).  QUESTION NO P127-7:  Where can I get a video praampli for a screen 17" Packard Bell model 3020 referred M52734SP?B & D Enterprises (800-458-6053) is listing Mitsubishi's M52734SP for $10.56 ea. QUESTION NO. P121-8:  15" Daewoo 1511B monitor (circuit board marked as 1509b).  Diode D504 is shorted and horizontal size is too wide.  This diode marked as S3L. I need analog list to repair this component.Shindengen's S3L rectifiers are ultrafast (Trr <35 to <50 nsec), 3 Amp devices.  Voltage ratings are S3L20 = 200V, S3L40 = 400V, S3L60 = 600V, so can you find the voltage-rating marking on your rectifier? If not, it is probably safest to try S3L60.  B&D Enterprises (800-458-6053) lists all three of those rectifiers in its inventory. QUESTION NO. P1124-10:   I am working on a Compaq QVision 172 Model 454.  Resistors R195 & R205 smoked.  Color bands are unreadeable.   Need values.R195 and R205 are 215 ohms, 0.5 Watt.

 QUESTION NO. P121-2:  Where can the focus block be purchased for the Compaq Qvision 200?  I have turned work away because Compaq will not sell parts.When you are dealing with monitors from computer BOX makers, these concerns do not make their monitors, they buy them from any of several subcontractors, so you HAVE to use the FCC number to know the OEM manufacturer. This situation pertains to Compaq's. Since you did not give the FCC number on your model, I can only guess, but if it is a 480P with FCC number starting with GZM1323, then the monitor is from Philips/FIMI.   You can get the focus block from a Philips parts supplier by using Philips' number, #4822 212 30169. In the US, NEI (800-634-7278) also has stocked these items.NEI @ 888-634-7278 has the original manufacturers (Philips) focus block for the Qvision 200 under part number 92611. The original focus block in my Qvision 200 has the pn 4191 AE 92611, but NEI uses only the 92611 as the part number. The price is $85. QUESTION NO. P1118-8:  I am repairing a TVM model MD-14v+T2+14" monitor which has a horizontal problem. It displays a single vertical line only.Replace C446 1uf/50v, c431 4.7uf/160v, c423 .0086uf/1.6KV.  QUESTION NO. P1116-1:  I have a problem with a NEC 3FG monitor.   The picture erratically blinks and the size of the picture suddenly increases and decreases.  I have no schematics for this one, I think it is a horizontal sync problem.Two possible solutions:  No 1 High voltage drive frequency too high. Replace zd508 6.2V 1/2watt zener,C581 10uF/50V,R5C8 39K,IC801 Sync processor HE60020. No 2 Try replacing high voltage adjust control VR15 Intermittent at the 20K to 22K surface area. QUESTION NO. P1113-7:  What components are suspect in a Macintosh 12" Family M1050 Monitor that has no power?There are four caps I often change on the M1050. CF1,CF2,CF3,CF6.   I have also encountered many of these monitors with a dim picture. The CRT needs to be restored.  I have done very well with Sencore's CR-70 for this. QUESTION NO. P1123-3:   I wish to split a VGA signal in two.   I want to connect two monitors approx. 20 feet apart from the one Industrial PC.   Can this be acheived without adding additional circuitry and if it cannot, what is the best and cheapest solution to the problem.I sometimes drive two monitors from one pc through a home-made "Y" cable.  The only drawback to this is that the video signal strength is slightly reduced.  This will vary depending on the monitors used.  There is a small chance that the other signals will seem to interfere with one another causing loss of sync. or a shakey picture.  If your installation will be somewhat permanent, you may increase the monitors' internal contrast to compensate for the reduced video.   Try the "Y" cable approach first. The worst that will happen is that you won't like the result. If you need something better or wish to drive more monitors, see the "Driving Multiple VGA Monitors" article on this site.  It offers an inexpensive alternative to a commercial fanout. QUESTION NO. P1024-2:  I have an AOC CM-335 monitor with poor horizontal deflection (ie 2 inches short, both sides).  There is no adjustment on the front, and no

labeled pots inside.  How can I make the display wider?You should look for a carbon core coil on horizontal ckt and adjust the core so the image is the way you want it. QUESTION NO. P1021-10:  I have several CTX CMS-1461 Zeos monitors. All seem to have the same problem, I replace the fuse on the main board and it blows when the power is turned on. What could be causing this?Replace zd 101 18v 1-watt shorted in power supply, Q101 2sh955 shorted sub 2sk956, r114 .39-ohm 2-watt 5% may be out by a few tenths of an ohm, ic101 uc3842 sub nte 7096 located in power supply on the daughter board, r113 100-ohm 1/4-watt 2% on daughter card, C113 .01uf/50V on daughter board in power supply and 2.5-amp input fuse. QUESTION NO. P1024-4:  Still working on that NEC 3FGx.  I have two burned resistors which were in the drain circuit of the MOSFET. Both appear to be 10 ohm 1/2 w flameproof but one measures 150 ohms and the other 180 ohms. They are circuit designations R557 and R558. Are these values correct or are they a different value?   Both are quite charred.Both r557& r558 are 390omhs 3w at 5% . QUESTION NO. P1117-10:  I have an ACER 7156 monitor.  After changing the hot (Q 305), the picture is OK for about 5 minutes.  After that, it is growing so I have to turn off the unit.  Is this a common problem with this model?An expanding screen indicates that the HV on the screen is dropping.   From the description of the fault, check that the HOT is being driven into saturation.  If it does not go into saturation, it will get "Hot" and its internal resistance may go up.  Check for leaky capacitor around the pulse transformer that drives the HOT. QUESTION NO. P1118-5:  The monitor I was working on had an intermittent crt yoke connection problem, in that the screen would have a tint of green. I could slightly twist the card that attaches to the yoke and the problem would come and go. Upon removing the card from the yoke a pin came out with the socket. Is there any way of reattaching the pin or is the monitor junk?Are you referring to the small rectangle of board that is attached directly to the top of the deflection yoke, or do you mean the larger PCB that is plugged in to the back of the CRT itself? If it is the board on the yoke, it should be a simple matter to just remove the wire from the jack and solder it directly to the base where the pin broke off from. However, if you are talking about one of the pins that stick out the back of the CRT, you might be out of luck. I had a monitor brought to me once with a missing CRT pin. There was enough pin remaining that I was able to solder a short piece of stiff wire to it and make it useable again. Check that scenario out. If the pin is broken off flush with the glass or less, at least you have a chassis full of spare parts for something else. QUESTION NO. P1024-5:  I have a KDS-1500 monitor. The problem is it blows out the fuse as soon as I put the power. To my understanding there is a short somewhere.  The relay does not get activated and there is no sign of burnt component. The problem is residing into the power supply.  I have disconnected everything cable that goes out to the other boards and it  stills blows out the fuse.

This sounds familiar! Once or twice a year I see this and it can happen to any monitor. Remove the degaussing posistor. If the monitor powers up (with an impure picture), replace it. I have also heard of the degaussing coil itself going bad but I have never seen this. QUESTION NO. P1027-6:  I have an IBM G70 and need the value of R101.  Also, R101 and CR105 were replaced. CR105 shorted R101 open. I tried a .57 ohm and it works somewhat. when plugged in, it comes up and stays. when unplugged and replugged in, R101 pops and opens. I can also hear faint ticking sound. HOT ok . When monitor comes up first time, it functions fine.R101 is a 0.33 ohm fusible-type resistor. QUESTION NO. P1113-4:  I am working on a Packard Bell model 1412SL, FCC#8JMCM14UP computer monitor.  I am trying to replace Q402.  It is a FET/unijunction transistor, part number K2160. Can anyone suggest a source for the part or a suitable replacement?2SK2160 is a Sanyo N-channel MOSFET, 200 V, 7 Amp, 25 Watt (insulated TO-220), Rds[on] < 0.45 ohm. B & D Enterprises lists 2SK2160 for $3.71; 800-458-6053, 814-757-8300; email sales@bdent.com. You could also substitute an IRF630 with insulating hardware. QUESTION NO. P1112-10:  I have a CTX CPS-1760 monitor, I need to know the value of resistor R109.R109 = 30k 5% 3watt. QUESTION NO. P1026-8:   I am working on a Daewoo CMC-1703b monitor with a wide screen and severely pincushioned.  I have two with the same problem. It is a pretty new unit and it is a Korean village inside.Check D502 for a short. It is a ST MDV04-600 high voltage ultra-fast diode. QUESTION NO. P116-2:  I have a KFC 14" monitor, 4 years old. It can only handle the sync. 60 Hz in resolution 800*600 pixels.  When I tried to set it to 90 Hz (in Win 95) there was a clicking sound in the tube, and the monitor turned into "sleep-mode". When I restarted the system, the green power on led did not show any activity. Instead the orange energy led lit and the monitor was giving a ticking sound. There is no high voltage on the tube. What could be the problem?Assuming that "it can only handle 60Hz at 800x600" means, that this is what the monitor's documents tell,- well then most certainly something went because you exceeded the max. horiz. scan rate. You can calculate the horiz. frequency applied at a given refresh rate from "vert.lines" X "vert.refresh rate" (plus 10% for safety reasons if you are near the limits of your monitor).    60HZx600lines makes 36kHz. Your 90Hz X 600 lines gives 54KHz, - which is too high for older monitors (38-48Khz). - Probably the Horizontal Output Transistor shorted out. If the picture had unusual width or low brightness before dying or it  collapsed to a vertical line or spot on failing this would confirm. If it collapsed to a horizontal line then maybe the vertical output IC died first, overloading the flyback and took out the HOT this way (plus maybe the flyback - so inspect it for cracks in the plastic that would indicate overheating). The ticking on power-up  you describe should be caused by a short circuit due to the shorted HOT.

If it is the KFC I think it is, you have blown the HOT.  Should be a 2SC4770. QUESTION NO. P119-3:  I have a NEC JC-1734VMB Monitor. When on, it only displays for a second then the HV will shut down.  However, the led remains green. Repeating the ON /Off sometime will get it up and it will stay good for the whole day until the next ON /OFF procedure.Since it will fire up sometimes, it is not a blown part like a HOT or FET. I think you need to read about IC801 in answer P1027-3 on this page. QUESTION NO. P119-1:  Compaq 440 and 450 15" and 17" monitors.  Where can I get the digital adjustment tool and software that plugs into the back of the monitors?These Compaqs are Zenith chassis.  If you are talking about adjusting the RGB values, only a few places (in the US) have that alignment software, and they will not share; they will want around $100 per unit to do the job. If you would rather try a workaround, you can probe the CRT board with a 10K resistor attached to its ground, to find the point that affects what you need. This probably will be near the base side of the driver transistor outputting that color signal to the CRT. Then you vary the value of this resistor (or use a trimpot), or raise the bias by attaching the resistor to Vcc instead of ground, until it adjusts the RGB to your desired value. Play a bit with the bright and contrast controls, to be sure the color stays correct, and if so, you are at the right point and can then wire it to the board. QUESTION NO. P119-9:   Working on MAG Technology 17" monitor model dx17f.  Unit keeps burning up R177.  This resistor is between b+ and horizontal driver ic.  Already replaced horizontal driver and flyback with no luck .Replace the following parts:C123 - 1uf 50vC120 - 1uf 50vQ103 - 2SD1887L105 - hroz. drive transformerR177 - 1ohm 1wattD116 - 30DF6Q116 - IRF740R181 - 120k 3wattC908 - 1uf 450vThis is your basic upgrade for all DX17 style monitors. QUESTION NO. P119-8:  Have a NEC jc-1741uma need the value of resistor r860 on the video board mounted on the back of the monitor.  I believe it is for the 13-volt supply for the cpu board mounted on top of video board.R860 =10ohm-1watt. QUESTION NO. P1028-2:  I need to have the part numbers or values for C350, Q350, and Q302 for model# RM07f11 on a 17" AST computer monitor.C350 is 1 uF/50V, the FET is IRF630, but that Q350 is an NPN digital switching transistor; try an NTE/ECG sub for that one. These are all pretty similar in function, except for the Collector current they're intended to switch; the NTE/ECG 2359 needs the least base current, but go to a 2357 or to 2355 instead, if the Collector current at turn-on would

exceed 5 or 10 mA, as the 2359 base's turn-on voltage would exceed 5V at such current. Also, to prevent damage from re-occurring, check 15 volt zener ZD301, off the FET's gate, and be sure the solder on damper D303 solidly connects to the board, maybe run a jumper wire through the hole, or these parts may blow again. QUESTION NO. P1025-5:  I am working on an NEC JC1531VMA2 (4fge) that lost highvoltage after I replaced the flyback.  The replacement transformer came out of a working set.  After replacing the high voltage adj. pot, the high voltage shut down.  Smps is good., H.O.T. is good.  What should I look for next?You probably have a very high high voltage and x-ray protection shuts it down.Try readjusting or change your trimmer pot again. QUESTION NO. P1023-3:  RE Answer P819-6 CTX 1565D, No raster. Have hi-volts, tube neck lights, will degauss ,computer power up aware.  Soldered CRT connections as advised. Still no raster. Could not identify a G1 or D2 to check. Would appreciate a kick in the right direction to get this to light up again.G1 and G2 Voltages are developed by the horizontal deflection circuit. They are necessary to produce illumination on the face of the CRT.  The G2 voltage should be about 1000 to 1500 volts at the source and must be adjustable to set the drive bias at the CRT. The G1 voltage normally is near 50 volts, in some cases closer to earth or even higher. Without a schematic of the circuit, it is rule of thumb time.  Also, the focus voltage should be about 5 to 10 % of the uther voltage. Anode voltage is another rendition of uther voltage. Of course, the filament must be illuminated for any theromionic conduction to occur, that is, to produce any beam current and even get a faint glow on the CRT. If you are unsure of the way to check and repair these circuits, you may consider taking the item to an authorized servicer. QUESTION NO. P106-6:  Packard Bell Model No1020 Fcc h41cm14011 Monitor.  No screen brightness.Picture is there and has contrast, but no brightness.I was checked drive on RGB drive on CRT but still not found which components are faulty.It sounds wierd but I would replace the ZILOG processor, they have a problem with heat. QUESTION NO. P114-10:  I have a CTX 1765CD that I got with my Zeos computer and occasionally the screen does a huge horizontal shift right and I cannot re-center it all the way. In a few hours all of a sudden it shifts back to normal position and it keeps doing this.Your problem sounds like bad connections in the horizontal linearity circuit.  I would resolder it. QUESTION NO. P114-4:  After 5 or 10 minutes of warmup, the horizontal deflection on a Magnovision DX17F would go haywire (compressing at far left and far right, and streching in the center). It now does it always when turned on. This condition only shows up in DOS (an entirely different boot HD) and on W95 HD bootup of Windows95 (when the desktop appears the deflection is OK).MAG has a upgrade that deals with the horizontal circuit, it may help.   Replace C123-1uf50v, C120-1uf50v, Q103-2sd1887, L105-horz drive transformer, R177-1ohm1watt, D116-30df6, Q116-irf740, R181-120kohm3watt, C908-1uf450v. 

QUESTION NO. P113-10:  I have a Nec monitor model JC 1532 (3FGX).   I need the pin-out of the monitor cable  (end to end, not just function).The end to end pinout of the 3GFx video cable is as follows: 15 pin computer             11 pin video pcbconnector                           connector1                                                   12                                                   33                                                   5*4                                              *25                                                   7*6                                              *4*7                                              *6*8                                          *Shield9                                                N/U*10                                             *9*11                                             *912                                                 1113                                                  814                                                 1015                                               N/UPins with an "*" are connected to both the shield and pin 9 on the video connector inside the PCB cable.Basically all are grounds. QUESTION NO. P107-3:  I have an IBM 8517 SVGA Monitor with no high voltage.   The green led comes on.  I replaced shorted mosfet, shorted horizontal outbut transistor, and an open  device (P5502).  I assumed the open device was a fusible resistor.  I did not know the value of the component so I replaced with a 1.6amp fast-acting fuse.  When powered up, a blank screen and heard the usual static crackle associated with high voltage upon turn off.  During one power up, the new HOT shorts and causes power transformer to squeal.  The yokes test OK.   I think the flyback is OK.  What's up?The ITC is bad. QUESTION NO. P114-9:  Maxtech 14", fcc idat19r3/ck-4148 vga monitor.  Display is compressed at the top 1/3 ,video is present, but dim with retrace lines. Replaced vertical ic, tda8172, no luck.  Voltages appear to be normal around vertical section.This symptom is caused by a bad TDA9103 IC, so try replacing that one. QUESTION NO. P114-7:  Have a Nokia 447x monitor with hv but no horizontal sweep. Yoke is OK.Aside from bad yoke connections, and bad solder on the small board inside the cover on the back of the yoke, other common problems are FET# T27, resistors R195, R205, R224, and shorts in centering transformer M3. To replace M3, you need to read off its part#, which begins with FM2525 or FM2565, etc. There are several M3's, and your Nokia model number is incomplete (is it 447X058? 447X158?  447X258? etc), so I can't tell what you have, but be sure you order the correct M3 type from Nokia, or (in the US) from Trillium, 919-829-9747. If the board uses those small thru-hole rivets for its 'vias', these rivets may be breaking loose from the repetitive heating/cooling cycles of running, and may all need

resoldering, on both sides of the board, or these problems can recur.I replaced M-3 (orderd from Trillium) T-27 ( P-channel Mosfet) and R224? a 47 ohm? resistor. This restored the raster but when I connected the BNC cables, screen would go blank. As it turns out the V and H BNC cables needed to be swapped, even though connected normally on a Qvision 150 the Qvision would work fine. Also the T-27 I replaced.  NTE2372 was supposedly not compatable.  I recommend ordering it from Trillium. QUESTION NO. P1029-1:  I have two Graphon monitors, one is a 225 and the other is a gq 230. The 225 had bad primary caps 100uf @ 250v which I replaced.  Now it has a high frequency whine when I turn it on. It will come on after a few minutes or faster if I heat up the primary side of the power supply. The 230 does not come on at all.You still have a bad cap or two in the supply. Get the supply hot and running then use freeze mist at the caps one at a time. You should find it real quick.   On the second set, will the SMPS fire up when unplugged from the set? QUESTION NO. P114-6:  I have a Samsung model cb-504xs chassis 14p-36ar.  Problem is vertical screen rolling, checked all caps rep. ver. ic-an5512.   Problem still exists.First double check the B+ supplys to the Vertical ic. Also check the SYNC input to the chip, you may find a over-valued resistor In the sync circuit. QUESTION NO. P114-5:  I need some help with two monitors, both of which would just tick when they are turned on.  One is a CTX VL700 the other is an IBM2124.In both cases the ticking seem to be coming from the power supply area.  In the IBM, the power LED would blink in sync with the ticking sound.The first thing to check on both monitors is the H.O.T. transistors.   The symptom you are describing is a short on the B+ line.  The reason the power supply ticks is because it is going into over current regulation. QUESTION NO. P114-1:  I have a Gateway model dx-17s monitor on the front it has 1776 vititron with pulsing power supply.  I found a leaky diode on the main board D508, I believe it to be a zener but I am not sure of its value.  I tried Gateway, got me nowhere.   I need the value of this diode or part # and anything else I might look for.  The monitor will not power up.  I can get all the supplies to come up if I disconnect the connector from the power supply board to the main one.  I checked each line for shorts, found none.  Horizontal out is ok.For starters, D508 is a fast recovery general purpose 400V 1A diode.   It is being used as a transient surpressor for the high-voltage B+ line.  You also want to check Q511 (fet IRF630), Q512(2sd1088), and D503(DO8M-15 - damper diode). QUESTION NO. P1030-6:   I have a customer with numerous Dell D1526T-HS monitors that need color/geom. adjustments. There are no internal adj. for these settings. The monitor is made by SONY for Dell and my customer spent a couple of hours on the phone w/Dell  only to find out that they no longer support this monitor and referred him to contact SONY. Does anyone out there have the software and cable or info. on where I can get it?You need the Sony digital alignment software/interface (DAS) package, and Sony will sell you this, but expect to drop roughly $1000, or more, depending on what

equipment/interfaces/cabling you already have or can wire up. I think this Dell is a Sony CPD-15SF1 chassis if so, the DAS connector will be a 4-pin connector with round pins near the flyback. If instead the connector is near the power supply and has flat pins, it is a CPD-15SF2. If your client has a lot of units, would they be willing to set you up for doing this service?  A financial/convenience case might be made for an ongoing service.You may be able to get what you need from Sony parts . You can find a parts supplier through Sony's web site. QUESTION NO. P1028-9:  I have an NCD computer monitor, model TX-T1536 NM2 ul# 1950 8b22.  I need to know values of Resistors 872, 873, 874, 875, 876, 896 and of Q 871. This had a blown mosfet, and burned resistors.If your NCD unit is a Panasonic/Matsushita make, the Viewsonic 15E is also a TXT1536 (made by Panasonic), so you might inquire from Viewsonic, at vstech@viewsonic.com, about those part values in their 15E, TXT1536 model. QUESTION NO. P1023-5:  I have a 13" Magnavox PR1310 C123 Ch.#13G602-00AA.   Dead, no power. Have replaced voltage reg. & npn horizontal deflection.and Surface mount fuse. Repair works fine for several months then reoccurs.  Is there an update or other suspect part?There is a service bulletin out on the G6 chassis for this problem. Order part number 4835-310-57404, a kit of parts and instructions.  Save the instructions and order separate parts from a cheaper source to fix subsequent units. I have two hotel customers with this chassis and the  fix seems to work well. This problem does not happen in all of these units, so just put it in the ones that blow the HOT. You may also order TV-TIPS and VCR-TIPS as microfiches from Philips, the clerk will not know they exist, but tell her to key in the names like I have typed them here. They are valuable sources of info on Philips products. QUESTION NO. P1022-9:  I have three Datatrain dc529p monitors, manuf. sept/95. All with same problem - extremely dim picture. Voltage across brightness pot =-29V. Same voltage on screen pin on crt. Cathodes = 100 - 110v. Caps in circuit all check good, suspect flyback. What specs should be for voltage readings on crt?The CRT voltages are correct.  You may have to bite the bullet on these - those are all gassy CRT's.  Datatrain did not have much luck with that run of Samsung CRT's, it seems. QUESTION NO. P1025-4:  I am working on a Rasterops model 2075 RO 20" monitor. The power supply makes a chirping noise for about 10 seconds and then stops.Just a little bit more info. would be helpful. Did you check the HOT? QUESTION NO. P1020-10:  I have a Sony CPD-15F13 (Gateway Vivitron 1572) that is dead except for a ticking sound coming from behind the power switch, near the vertical xfmr. Tick rate is about 6/sec and it continues for about 5 secs after power is removed, gradually slowing down and stopping. The unit has video applied. Neither LED near the power switch is illuminated.Check the H.O.T. it's probally shorted. QUESTION NO. P1014-7: I am having trouble diagnosing a Daewoo 1705B 17" Monitor.   The width of the picture will flicker and then periodically go beyond the bounds of the

screen. Once that happens, the horizontal controls make no difference (pincushion, trapezoid, etc.). This problem is intermittent and does not occur all the time but it is increasing lately. What do I start checking and has anyone seen this before?First of all is the problem physical or thermal?  If it is thermal - freeze spray will help locate the bad part.  If it is physical - look for bad conections in the horz. circuit.I have had the same problem with a Daewoo 1707B.  Replacing D605 or D606 solved the problem. QUESTION NO. P113-8:   I have a Hitachi SuperScan 17s monitor, it had a cold solder joint on the yoke.  Now that is fixed, I need to set the rings on the yoke to get the color gohst out.  I can get it close but not completely.If you can get it close but not quite all the way the yoke is out of position.  Hook set up to a pattern generator , set the generator to red screen, adjust yoke for best purity.  Ounce the purity is set the rest should align properly. QUESTION NO. P104-4:  I have a Gateway 1776LE (MAG MX17) which lost RED drive.  Any idea where I should start to debug?You should start with the input conector on the crt pcb. Using a scope follow the red path.  You should find a shorted transistor or two. QUESTION NO. P1029-4:  Dell D2026T-HS Computer Monitor (seems to be Sony GDM20-E03) FCC-ID AK8GDM20E03, Sony-ID SCC-K18A-A.  Picture is only bright white with about five flyback-lines.  UG2-Voltage is 0V.It is possible you have a bad high-voltage transformer.  Remove the crt pcb from the crt, turn the set on and recheck the ug-2 voltage.  If you still have no voltage the high-voltage transformer is bad, if you do have voltage it may be a shorted crt.Just solved this exact problem on my Sony GDM-20E01 FCCAK8GDM20E01 SCC-G96A-A; On CRT board, there is one 3.15A solder-in fuse marked "SOC 315"; I replaced it and got all video-drive back; my prob was caused by accidental shorting of a B+ line while troubleshooting another problem. QUESTION NO. P1027-10:  CTX 17" monitor model 1785S.   Gradually gets brighter over a period of about an hour.  Adjusting the brightness control to a minimum still does not take the brightness level down enough.   Have adjusted 'screen' Pot on LOPT but this has no affect at all.>From the description of your problem it sounds like the screen control ground lug is broken loose from the pcb. Or the high-voltage transformer is bad. QUESTION NO. P104-3:  I have a Sony videoscope monitor model KPR-M360 that is apparently dead, no filaments in the CRT's, front power light comes on reluctantly, +18 and -18 measures 12 volts either side. Any hints for this problem?There are a number of pico fuses on the deflection pcb that start with the prefix PS.  The most notorious is the vertical feed.  You may have a bad vertical output. QUESTION NO. P1027-8:  I have an IBM 14" monitor that will not sync properly.  It is labelled 2248 on the front and has type 96G0134 written on the back.  Can you confirm for me that this is a VGA or SVGA monitor and not a XGA monitor?  If it is an SVGA

monitor,  do you have any tips on what might be wrong with it?I have looked through IBM for that model number and cannot find it.   Chances are it is a fixed frequency monitor. If you recheck the numbers on the monitor you cam go to RESTORSTONE at http//www.restorstone.com/monitormanu/searchmainint.html or GRIFFIN at Http//www.nashville.net/~griffin/monitor.html. QUESTION NO. P1030-5:  I have three Sun/Sony GDM20D10 (3651167-010) 20" monitors that have low brightness.In order to readjust the brightness you will need to get sony's adjustment softwareand adaptors.You will need a cable and software from sony to adjust this unit.   You will also need a computer , a programable signal generator, and the service manual to do these adjustments. QUESTION NO. P1022-1:  I have this HP D2818A. All the voltages are OK, the picture is present but very dark. Brightnes and contrast controls are working, but picture still way too dark. The CRT is a Samsung unit.A dark/dim Samsung CRT is usually a bad CRT, especially if the voltages are good. Common problem, and they do not restore. If you have not done so already, you might just cross your fingers and check the filaments for correct voltage or ripple, in case the filament supply filter cap has gone bad, or the G2-to-ground cap. QUESTION NO. P1027-3:  I have a NEC monitor (JC1734VMA), when I power it on I get no video. However, if I turn on the monitor before the PC is connected then connect, I have video. I also noticed if the PC is connected and I toggle the monitor on\off\on just righ, it will fire up.Check out IC801 = UPD78014YCW-Y22 (or -Y24), see if heat or freezespray on IC801 affects the situation. If bad, not good news.  the preprogrammed IC801 IC's are expensive; NEI (888-634-7278) wants $$ for these IC's. QUESTION NO. P1027-5:  I am working on several Sony 15" CPD-15F13 Vivitron Monitors all with similar problems. Monitor works fine except a red tinted screen. There are no pots to adjust on these monitors for any RGB balance adjustment. I suspect the CRT's have emission unbalance between guns to cause this problem.You need a special jig from Sony that hooks up to a computer.  But all is not lost, you can TRY readjusting the screen voltage which will change the auto tracking on the crt.The color balance on these units is done using proprietary Sony digital alignment software too expensive to get for one job, send these out to a shop that already made the investment. QUESTION NO. P1028-6:  Repairing a Dell P1728U found a bad scr but the number will not cross to ecg.  The location  is Q524 and the number on the part is J307.The J307 is a 2SJ307 and are available from DALBINI 800-325-2264.J307 is 2SJ307, a 250-Volt, P-channel MOSFET, not an SCR. You can get one from MCM (800-543-4330) or B & D Enterprises (800-458-6053). QUESTION NO. P1022-10:  I have Highscreen SV 28/3 monitor. If I change resolution, display moves and change dimentions very much.  Manual controls of size and position are OK.

The monitor can not handle the refresh rate in that screen size.   Lower the refresh rate or change your monitor driver. QUESTION NO. P1026-1:  I have a Samtron 14" monitor model sc-428vs FCC csysc-428vsp. The problem is no video or raster on the top half of the screen.  I have checked all components in the vertical section and changed the vertical ic. I am looking for the pin layout for the vertical ic TDA8351 or any help on this problem.Here is the pinout for a TDA8351:  Pin Symbol Description:  1 I drive (+) Input power stage (positive), 2 I drive (-) Input power stage, (negative), 3 Vp Operating supply voltage, 4 Vo(b) Output voltage B, 5 GND Ground, 6 Vfb Input flyback supply voltage, 7 Vo(a) Output volatage A, 8 Vo(guard) Guard output voltage, 9 Vi(fb) input feedback voltage .---..---.Idrive+ 1<| '' |Idrive- 2<| | Vp 3<| |Vo(b) 4<| |GND 5<| |Vfb 6<| |Vo(a) 7<| |Vo(guard) 8<| |Vi(fb) 9<| |`--------'Pinout of TDA8351 is 1) Input power stage(+), includes Ii(sb) signal bias; 2)Input power stage(-), incl. Ii(sb)signal bias; 3) Vcc; 4)Output Voltage B, 5) GND, 6) Input flyback supply voltage; 7) Output Voltage A; 8) Guard output voltage; 9) Input feedback voltage.  NOTE Metal back of IC connected to pin 5.  The guard circuit blanks the display during flyback, if there is a short-circuit of the yoke or short-circuit of the output pins (pin#4 = sawtooth, #7 =drives yoke) to Vcc or ground, or an open loop, and when the IC's thermal protection is activated; Pin#8 goes to 5 V when the guard is activated. Aside from this, see if your new IC is overheating. If so, first check if Vcc at pin#3 (usually 15-18 VDC) has any AC ripple (bad filter cap). Also, off the flyback supply at pin#6 (usually 27-36V),  check the current-limiting resistor and cap on that line. Sometimes, the aging of components requires that this resistor's value even be increased somewhat from the original value, until the TDA8351 no longer runs excessively hot.May be best to get a complete pcb fom Zenith parts. Get the 9-XXXX-XX number from the original pcb and order the complete module.  A blown resistor is indicative of other problems within the circuit. QUESTION NO. P1026-7:  Applevision 1710AV, unit is dead with no video, no HV. I know there is a warranty extension on these but I have a customer who is 200 miles from warranty station and is willing to have me repair it IF I could get some help. Does anyone have any experience in component level repair?The biggest problem you face is APPLE PROPRIETARY COMPONENTS. Apple has released no information on this monitor (I know I have looked).  Apple will ship an empty box with a call tag to the customer so he will not have to drive 200 miles.   The average turn around time is 10 days. 

QUESTION NO. P1021-1:  I need a VEY09P RGB output IC to suit a TEKTRONIX 119-4980-00 monitor as TEKTRONIX will not supply parts.Can you suggest a   source for this IC,either in AUS or USA?  Monitor is made by Matsushita, who also will not supply parts.Both Panasonic and Viewsonic use VEY09P in their own monitors, such as Panasonic's C-2192P (chassis# 21HV4S), or Viewsonic's 21PS (2182PS).  I cannot speak for Australia, but US Panasonic distributors are usually willing to supply VEY09P (having stock is another matter). Did you tell the Matsushita sales rep your unit was a Tektronix? Tektronix would be an OEM client for Matsushita, and manufacturers often refuse to sell spares that might undercut their OEM clients, even if they sell the spares for their own models.  In the US, CCS (Computer Component Source) is one source that stocks VEY09P, US phone is 800-356-1227, Int'l. phone & Fax 516-496-8780, -8784. Viewsonic also supplies VEY09P for its monitors, 800-888-8583; 909-598-8673; email vstech@viewsonic.com QUESTION NO. P1013-9:  I have a Sun Microsystems monitor model GDM-20D10 that is not powering up.  Could anyone tell me where to locate any information on the operation and layout of this beast?This is the same as the Sony GDM-20D11. You can get the schmatic from ANATEK, or MI TECHNOLOGIES. QUESTION NO. P108-8:  I am working on a Dell D1728-L5, Video comes up Dim (Flyback OK).  Have checked caps, LM1203. I do not have pin out for Sencore CR70.   If not tube, can someone help?If you have a CR70, you use socket 3, video 2, bias 100v, filiment 6.3v. QUESTION NO. P102-5:  I have a Radius PrecisionColor Display 20 Monitor.  I have been able to make adjustments with both outside and inside controls.  However, I cannot find an adjustment for screen image rotation or scew.  Right now, the image is tilted about 1/4 inch clockwise.You need to loosen the yoke and readjust it. QUESTION NO. P1014-4: I have three Link LM1791DES monitors with the same problem. Each continues to blow the BU2525A yoke drive transistor.  I have replaced the transistor and associated caps and the yokes ring out ok. All  geometry controls work and there is no distortion of the picture.The units will run (hot) for about a week before the yoke driver blows again. I do not know that brand - but be sure that BU2525A is the original HOT!  Subbing Japan types (2S..) with European (BU-) type HOTS has not always worked for me- though the newest ref. tables say so. (BUs worked at textmode but fried at VGA and above).- Maybe you want to download the datasheet of BU2525A from Philips semiconductor and see for yourself.-  Quote New generation, high-voltage, high-speed switching npn transistor in a plastic envelope intended for use in horizontal deflection circuits of large screen color television receivers(!) up to 32 kHz(!).  Other than that, I would check for bulged caps in deflection (but that should cause abnormal picture size in the first place) and the flyback being cool (maybe ring it).  What about the HOT's base drive signal? Schematics would be ideal for checking that, but anyway at the end of scan there MUST be a clear and SHARP edge for the HOT to shut down properly.   (neg. spike at the end of scan going >5V below GND and the base stays negative until HOT is triggered again).  Look for any cap (parallel

to a resistor) driving the base of hot from drive transformer- even on (slow) TV-defections if this one loses capacity the hot fries. Maybe it is even the cap filtering the supply at the primary of the HOT drive transformer that has gone. That would reduce AC current through primary and thus weakening/distorting current@secundary thru B-E of HOT.I have experienced similiar problems that you have described.  Set working fine but HOT runs at higher than normal temperature then fails. This indicates that the transistor is not switching on hard enough or there is a failure in the circuit being driven. As the other reply, suggest it is worth checking the DC voltage present on the primary of the pulse transformer. Should be a steady DC voltage if not suspect that the filter cap has gone bad. In my experience, replacing the bad cap fixes the problem.In reference to the Link monitors, I have a WYSE model WY-1791DES (FCC ID HSUTRLDN-1782).  That I believe is the same monitor.  It also has a shorted Yoke Drive Transistor (Q420) the original part # is BU2527AX. I have not looked at the spec differences betweeen the and the BU2527, But perhaps you should be replacing the 25 with the 27? QUESTION NO. P106-9:  I have a Samsung Syncmaster 3NE monitor Model No. CVP4237L that I am repairing. I now have the monitor working after replacing the HOT. I need to do a basic alignment and I would like to know what the FBT B+ reference voltage should be.   I have set it to 90V, is this correct?The B+ adjustment for the Samsung 3Ne monitor is:  Turn on monitor and display a full white screen at maximum brightness and contrast. Connect a DVM from TP1 - +150 volt (beside T402 the FBT) and ground.  Adjust VR601 and set to 150 volts. Your guess at the 90 volts was close. It is about 87 volts. QUESTION NO. P930-8:  I have a Philips FSR871CV monitor (C2082-DA) where  I have located a blown IC. Need help to identify U4 on the Low level signals board. It is a Texas 8 pin IC but the rest is not readable. Any other ideas why this IC did blow?In an Epson unit that is also a Philips/FIMI chassis, the U4 on the low-level signal daughterboard is a Texas Instruments TL072CP dual opamp.  QUESTION NO. P1013-2:  Apple monitor, m/n 1787, fcc id BEJCA453, Goldstar chassis # CA-20.  Unit is dead, looks clean inside with low hours.Check the fuses, including any solder-tail ones mounted on the board itself. These often blow due to the degaussing posistor, their value is marginal. Replace fuses with 2.5 Amp slow-blow types. If the fuse still blows, try detaching the degaussing posistor and powering up. If the fuse now survives, the degaussing posistor may need replacing. QUESTION NO. P929-3:  I have a 1993 Dell Vi1428U monitor with a fast flashing power led, no high voltage. Speed of pulsing is similar to an unset VCR clock display.   Monitor looks very clean, no burnt components, no cracks on board. Any idea? Power supply?Listen carefully to the power supply. If it is ticking or chirping, suspect the HOT. If not, check the video connector pins (PC end).  A bent pin(s) that disables sync. signal(s) will place the monitor in power save mode if it is so equipped. QUESTION NO. P107-5:  I have a monitor Addonics 142 LR that loses one color after 20-30 minutes! What could be wrong?

My first guess would be poor solder on the CRT neck board or any other board the video signals travel through. The CRT neck board runs fairly warm so it is subject to heating/cooling stresses that crack solder as well as make the failing connections intermittent. I also find it worthwhile to spray contact cleaner into the video connector (PC end). This is not likely your problem but I have seen colors change their level because of dirty pins. QUESTION NO. P930-3:  I have a problem about monitor for vehicle inspection system manufactured from France (Philips) model muller bem.  The problem is vibration images.  What should I do first?The first thing I check is the big electrolytic cap after the bridge rectifier at the primary end and then the electrolytic caps in the HT line at the secondary side.Check for liquid near the caps. Or touch their legs with the soldering iron and if you smell something really nasty, that´s it. QUESTION NO. P107-2:  Can anyone tell me the correct values and power ratings of R109 and R113 on the deflection board in an Apple/Macintosh M3502 monitor?In the M3502, R109 = 22 ohm/ 2 Watt; R113 = 10 ohm/ 3 watt QUESTION NO. P103-1:  I have a MAC 21" monitor with horizontal problems.  I am looking for the value of the resistor R113.   Can anyone tell me the value?IF your 21" is Apple model M3502, not one of the (several) third party makes, then R113 should be 10 ohm, 3 Watt. QUESTION NO. P102-10:  I have an HP monitor FCC ID No. A3KM043.  Location 7402 Vertical IC.  Can anyone tell me the part number?If the FCC number is truly A3KM043, the Philips CM2099 monitor has the same FCC ID number, and the vertical deflection IC in that monitor is TDA4860, a 9-pin SIP.  If the FCC should be A3KM039, then an Apple M9102LL/D, with that FCC ID number, the vertical deflection IC is TDA4860, a 9-pin SIP. QUESTION NO. P101-6:  I have an HP monitor FCC NO A3KM043 Model NO.D3858A. The Vertical IC was burned out, I cannot read part number at location 7402.The Philips CM2099 monitor has the same FCC ID number (A3KM043), and the vertical deflection IC in that monitor is TDA4860, a 9-pin SIP. QUESTION NO. P104-6:  I am working on a PB1512sl FCC ID BEJCP510 (Goldstar) monitor.  It has an intermittent problem with the screen brightness wavering which also affects raster size and focus slightly. I can mimic the problem by wiggling the screen and focus controls.  The symptom does not seem to respond to vibration or freeze spray.  Am I correct in assuming this is a problem in a voltage regulation circuit, and do you have a suggestion as to suspect components?Wiggling the screen focus controls causing the problem would indicate a problem either with the physical controls (that is FBT assembly) or the connections from the fbt to the pcb. QUESTION NO. P105-5:  I have an NEC Model 3FGx with ZD520 and Q512 burned beyond recognition. What are the part numbersof these two components?

Q512 is a 2SK752, ZD520 is a RD8.2. QUESTION NO. P104-8:  I have an Acer 7176I which is all dead, not even light in power LED (the fuse is ok).Sounds like smps failure. Have you checked the H.O.T.? QUESTION NO. P103-5:  I have an AcerView 17" monitor, model 7176I, FCC id JVP7176I. The screen is out of focus (evenly across the entire screen image), but I cannot find the focus pot on any of the three PCB boards.There should be a pot on or connected to the flyback transformer.  If not, you will find it on the crt pcb. QUESTION NO. P930-4:  We have a problem finding  flyback transfomer for monitor model muller bem. Charactheristicof flyback transfomer  model DIEMEN 95-22 HR 11P 6362-01For information on HR Diemen flyback transformers, contact HR Diemen in Spain for assistance, either by email at  HR@hrdiemen.es, or on-line assistance at  http//www.hrdiemen.es/. QUESTION NO. P928-5:  I have a Mitac 17-inch monitor model# m1758.  The problem is when monitor is turned on, you can see arcing all around picture tube dag .The monitor works just fine except the focus is a bit blurry in the top left corner.  Can not seem to find what would cause this problem.You might want to try using TV CORONA DOPE (GC part # 10-5002).   Remove the second anode and repaint the tube around the hole.  This may help your problem.Arcing around the dag coating is indicative that the ground return some how is open. Either the dag coating has failed or the ground strap return to the chassis ground has opened. Having poor focus in only one quadrant of the screen would indicate that probably something within the crt has moved. If the focus in all the rest of the raster is good then you should be able to rule out the focus/hv supply as the cause. Is the purity also affected only in the same area? QUESTION NO. P925-6:  I have NEC JC-1531VMA monitor with problem. Both sides of picture are bowed outside ( ).  Picture is clean.  Adjustment from the front panel in service helps slightly.The common problem that causes this symptom is that C561 = 470uF on the main board can leak electrolyte, damaging traces on the PC board. Remove the cap and check underneath: if this cap leaked, you'll need to clean the board well, check all nearby traces carefully for damage, and to jumper any damaged traces. Even with no loss of continuity, leakage onto the trace from the wiper arm of pot VR403 to pin# 8 of board# PWE317E can actively cause problems, so you may need to actually CUT that trace at both ends, and jumper between the cuts. Note, the leaky cap may actually test good, but replace it anyway with a 50V cap. Cap C557 can also get leaky and should get checked, too. A bit of conformal coating or lacquer on the PC board after cleaning well can be a future safeguard. Secondarily to this problem, if it still will not adjust, and you're sure you caught all the damaged traces, check IC4E2 and IC4E4 on board PWE-317E, check that there is 53.5 Volts across resistor R409 on the main board, and check C523.

There is not 53.5 V across R409. It varies with the witdth of pix as low as 27V to 35 Volts. QUESTION NO. P925-2:  I have five MAG DJ530 monitors (model no. XBO504-01 / FCC ID # IAWXBO504) all were made in early 97. All are dead no power no led (green or amber), HOT  is OK.  Could this be an eeprom problem? HELP!Check the regulator IC in the power supply for the 5 Volt line, and see if it is outputting 5 Volts.  If not, replace it.  If the regulator IC is a 78M05 type, upgrade it to a 7805 type. QUESTION NO. P922-7:  I have an Apple M1823 that would not fire at all.  I determined that the flyback was bad, and replaced it.  Now it fires up briefly, and then the orange light just flashes.  It has a good signal coming in with both h and v sync the proper frequencies.  I have determined that the horizontal sweep transistor, Q512, is not getting any voltage on the collector.  Q511, IRFI9630, had 50 volts on the Source and Gate, with a signal that does not really look good, but the transistor is not switching.  I am not sure if the problem is insufficient gate drive, or if the voltage is wrong or something else is wrong.Check if any of the picofuses (PS500, PS501, PS800 = 1.6 & 1 Amp types) are open. If Q511 is leaky (may test OK), replace it.  Also check   R851 & R868 = 2.2K, C822 = 470pF/2KV, D504, D824, D825. If still shutting down, and HV is not over 27 KV, check out/replace IC404 = TL082 opamp; check out/ replace IC801 = 4049B CMOS logic IC. QUESTION NO. P921-8:  I have an IBM 8512-003 VGA monitor that has a high pitch sound coming from the power supply. The picture is wavy, but is still very clear. Could anyone help me with a remedy to this problem?First, replace C120 = 10 uF in the power supply, use a 105°C cap if you can. Also check fast recovery rectifier CR105, and, near the flyback, 3 Amp, 600 Volt rectifier CR212. QUESTION NO. P919-3:  Mitac L1450PD monitor. At switch on the power supply output is low at about 80V and the unit makes strange noises. If it is left like this for 20 seconds, switched off then back on, the unit will work fine for the remainder of the day. I have checked the caps in the primary and secondary of the power supply with a ESR meter and changed the faulty ones but the problem persists. Any suggestions?In later production runs for this chassis, the manufacturer upgraded capacitor C926 from 100 uF to 220 uF.  Does your unit have this upgrade? QUESTION NO. P925-5:  We have several IBM G50 and G41 that have HV problems. The HV leaking from the FBT. First we suspect the FBT itself but we are not sure. It could be that the HV is too high. The picture is OK.Reading your question states that hv is leaking from the fbk. This would indicate to me that the insulation of the fbt is breaking down causing a path to neutral for the hv. Only cure that I have found that works is to replace the fbt assemblies. You may try applying a sealant to the fbt but I will bet it will not stop the short. QUESTION NO. P915-7:  I have an Apple monitor model m2943 fcc # bjmcm15vb.   The unit runs for one hour then shuts down, green light stays on.  I replaced pwb-1822, no fix.This unit may have a factory extended warranty.  These units were LEMONS.  Check out Apple'S web site for more details. 

QUESTION NO. P923-4:  Could anyone tell me the spec of an oldish Sony monitor model GDM-1952?  I have also seen these badged as IBM's, and neither of them will sync from a vga card.A lot of these units are fixed mode VGA not Super VGA and will only run on 640x480 mode.Specifications and notes on the sony gdm 1952. This monitor syncs exclusively to the resolution of 1024x768 at a vertical scan rate of 60hz and horizontal scan rate of 50khz. You might get it to sync to the resolution of 640x480 at 60hz but, this is unadvisable since on a crt of this size this would give huge text and icons and very little desktop space. It is designed for 1024x768. The only drawback is the noticable flicker that the 60hz refresh rate produces. If you have the sync on green version of the monitor or video cable you can compensate with sync on green adapters excluding certain newer computers and video cards. The optimum would be the external sync (5bnc board on monitor) and 5bnc 2hd15 or db15 video cable. I have found in most cases that the best way for first time setup is to fire computer up with multiscan type monitor first, access display control panel and select resolution of 1024x768 at 60hz. Without shutting computer down, transfer gdm1952 over. QUESTION NO. P919-6:  Monitor Model M152 PNLD, made by S.A.M. GmbH FCC ID IQX93C 1564.  This model has a dim picture on Windows 95 opening screen, for example.  But when I click on shut down, the display changes to normal. I have replaced the video ic LM1203 but no difference.This looks like a video card and/or video driver issue rather then monitor problem. There are two ways to find the guilty party 1. Restart PC to real DOS mode (click on Start, Shut down, Restart in DOS mode, OK). After restarting, at the DOS command prompt, type in dir/w and hit Enter button or start one of the old DOS based game 2. Connect the monitor to another, known good working PC and power it up.  If you have good quality picture using 1), reinstall video drivers for your VGA card. If no change but had a good picture using 2), change VGA card. QUESTION NO. P919-8:  I have a monitor Compaq model 420 with the problem that the display becomes squeezed, which curve at the both sides.Sounds like the main capacitors in the 115V power supply. You can jump them with the same values or pull them and test them. But you probably have one or more going bad. QUESTION NO. P918-4:  I have an older, Sony MultiscanHG 17 inch monitor, it turns on only when it has been off for a long time (many days). If I try to turn it on a day after I used it, it makes a whistling sound that grows in pitch, stops, and the power up is stopped.Heat the set up and let it fail. Leave the set on and hit the capacitors in the high voltage power supply (around the flyback) with freeze spray. If there is no response, try the main power supply. Sounds like a capacitor somewhere in the set is leaky and after a while becomes sensitive to heat and voltage. QUESTION NO. P93-8:  I am working on a CTX monitor model 1560Lr. After powered up for 30 to 45 minutes, the pincushion starts to vary by itself and then the screen flutters horizontally. We have repaired many cold solder joints but nothing has helped. Hit all of the capacitors around the pincushion and flyback with freeze spray. If it is good when first turned on, then probably a leaky cap.

 QUESTION NO. P923-6:  I am new to the business of monitor repair, and I am currently working on four Applevision 1710 displays, FCC ID# BCGM2935. All four have the same problem, that is, they power up (LED is green), the high voltage is ok, the CRT charges and remains charged, but the monitor will not display anything (screen remains black). Working on one of them, I replaced electrolytic caps CF1, CF2, CF4, CF8, CL49, with absolutely no results.The Apple 1710 model requires information from AppleVision software drivers in the computer, uploaded via the video cable, or you get the "no video/green LED" symptom.  In addition, many of these units, those with serial numbers from SG522xxxx up to SG628xxxx, have problems requiring a repair under Apple's extended warranty program, available until 12/31/98.  To get the details of how to re-set the display with AppleVision software, or how to qualify for the extended warranty service, go to webpage http//til.info.apple.com/techinfo.nsf/artnum/n58001.The problem seems to be on the crt board\processor board with bad solder and mainly on the surface mount components.  I have had luck reworking iv2, iv4, iv6. QUESTION NO. P918-7:  MAG DX17 monitor with a bad transistor at location Q116.  It is marked as a K1378.  ECG and SK did not have it listed.  Any ideas as to what might be a cross for it?That should cross to an NTE1378, as I had to replace this in my Gateway 1776LE unit.2SK1378 is a Toshiba MOSFET, rated 400V, 10 Amp, Rds[on] < 0.55 ohm, 125 Watt. For the DX17 monitor you have, IRF740 should cross for 2SK1378 Mouser (800-346-6873) lists IRF740 for $2 - $3, depending on manufacturer (EXL, SGS, or Harris), and TechAmerica (800-877-0072) prices similarly. If you prefer using 2SK1378 itself, B & D Enterprises (800-458-6053) lists this for $8.58 or MCM Electronics (800-543-4330) for $4.38 (MCM's minimum order is higher than B & D). QUESTION NO. P98-5:  Tenemos un monitor IBM 6543-302 con insuficiente e incontrolable anchura horizontal, estando a la vez fuera de frecuencia.  ¿Podeis ayudarnos?La averia que tiene ese monitor es muy comun tienes un condesador electrolitico seco, normalmente llevan tres condensadores cerca de la deflexion horizontal cambialos los tres y ya esta. Para encontrarlos sigue los cables del yugo de deflexion de horizontal. QUESTION NO. P917-2:  I have a CTX CVP 5468 NI  with a horizontal sync problem.  Monitor came in for flickering picture, seemed like bad solder connections.   Resoldered.  Searched Dejanews.  One reference to the 5468 said that Anatek had an extensive database on this problem?  Where can I find it at?Regarding the monitor repairs database, you may mean   Anatek's new DataDirect CD, general repairs database, or the Resolve Monitors Repair Database (see info on this website).  In the meantime, try freezespray on the LA7851 IC in your CVP-5468NI, and see if it affects your sync problem. QUESTION NO. P812-8:  I have a Packard Bell PB1412SL that came in with a shorted H.O.T. (2SC4619).  I replaced it with a ECG2353 (2SD1881).  It works fine except when it goes into low power standby, it blows the H.O.T. again.  B+ and Vp-p are normal and a quick check of surrounding components yields nothing. Customer becoming upset.  Any

thoughts?I had the same problem when tring to use the cross ECG 2353 for the Toshiba C4619. Seems like the chassie design does not like the ECG 2353.  If you look at the knot on the 2353 it will work with most applications. But not this one.   Use the 2SC4619 and you should be fine. QUESTION NO. P94-1:  I have a problem with TELEFUNKEN chassis 615 A1.  Switch on is correct but no image, the screen is black, the horizontal power transistor does not work.  I checked the driver but it is OK and replaced the C.I. TDA 1940 oscillator H. but it does not work.  I checked Q482 it is OK.  My big problem is I do not have a scope.We need more info. Do you have all of the smps voltages?You can try COMPUTER COMPONENT SOURCE at 1-800-356-1227. QUESTION NO. P824-8:  I have a question regarding a 17" monitor.  I need to know where I can find the transformer (serial inductor) that generates the B+ to the flyback. The brand of this monitor according to what I found on the back cover is Fair Electronics, new to me.You could try Conputer Componet Source at 1-800-356-1227. QUESTION NO. P812-6:  I have  Premier aa1450 (fccid# mm3cj-480n) VGA monitor.  The company that manufactured it is Chang Jun Technologies. I cannot find any way to get a schematic for it.  R522, which goes to pin 3 of the flyback, disintergrated just leaving a scorch mark.It may be a low ohm fuseable resistor (1 to 10 ohm).  To help further we need to know what circut it feeds (ie vertical, pincushon, etc.) QUESTION NO. P819-6:  I have a CTX-1565D that will power-up, but will not show any video.  The CRT heater is working and there appears to be high voltage.  I have seen other CTX monitors with a similar problem.  Do these monitors have a typical failure mode?  I do not have schematics.For 1565D usually there is need to resold CRT socket. Check G1 and D2 anyway. QUESTION NO. P827-5:  I have a CTX CVP-5468A monitor with low brightness and slightly too-wide display.  The owner's complaint was only the low brightness.   He said this happened suddenly.  I do not know if the over-width happened at the same time.  There is barrel distortion on the right side, and the top and bottom are slightly wavy.  Only the left edge is dead straight.  The monitor is stable, hot or cold.  Nothing looks fried.  The B+ is correct at its marked 104v.   The HOT and flyback run cool.  Screen and focus pots are paint-locked at factory settings.  The auto-sync works well.  The colors are very good.   Linearity good.  I am trying to figure out what single "sudden" failure could account for these symptoms.Horizontal size and brightness change at the same time if HV is wrong.  Check HV regulation circuit. QUESTION NO. P826-10:  I have a NEC 4FG, Model jc1531 VMA, with bad side pin Cushion )(.  I already checked C561 for leaks but do not see any.  What else can I check?I cannot tell if your inspection of C561 for leaks was good enough. Did you read the

Monitor Answer# P527-4, including the part about C561 seeming OK? Did you do everything that answer indicates?  Checking continuity of traces and cleaning underneath C561? Jumpering the trace from VR403 to PWE317E? Testing the IC's on PWE317E?   QESTION NO. P817-3:  I need information about an IC (included in a monitor 4FG,15"Nec) VPS08N.  I have tried many different sites, there was no information.  Can you help me to find datasheet for this IC,  it is only for testing purpose, if the ic is OK.VPS08 is a Sanyo 3-channel, 80 MHz CRT video output driver. It is obsolete, so the Sanyo website (www.elisnet.or.jp/login-sanyo.htm) does not provide its datasheet. But you might download the datasheet for VPS10, which has similar package and voltage ratings, though rated for 100 MHz. VPS12 and VPS13 also exist. In the meantime, you might also check the traces beneath your VPS08N for corrosion due to leakage from cap C793, which is a common problem in NEC 4FG's.  QUESTION NO. P98-9:  I am working on a GVC 1450C that had a blown HOT transistor.   The ID # was a C4916 which crossed to a ecg 2353 with a note stating that it might not be the same electrical or mechanical match but works in most cases. So I throw one in and bring it up on a variac, everything seems fine. I run the monitor for a few hours turning it off and on every so often, worked fine.  The customer takes it home plugs it in and it dies.  Is this replacement part one of the few that will not work with this application or is there something else I am missing? I noticed that the ecg 2353 and the nte 2353 are not exactly the same. Wonder what the values were on the original C4916?It is a risky proposition using "universal" type subs to replace HOTs; you cannot just rely on the usual Volt/Amps/Watts ratings to pick a substitute.   Differences in gain, capacitance, and inductance will affect how easily the HOT can be driven, so you just cannot assume that even a higher-rated device will sub for the original in the particular circuit in your unit.  A beefier HOT (or one with the same Amp rating but insufficient gain) is usually harder to drive, and will overheat if underdriven by the existing drive circuit, as its saturation voltage will be too high.   A device that is overdriven (or has too much gain) is too slow to turn off and will dissipate excess power, while a device that turns off "too fast"  just may suffer excessively high inductive voltage spikes. With regard to 2SC4916, that is a Toshiba device, rated 1500 Vcbo, 7 Amp, with an internal  damper diode. Union Electronic (800-648-6657) sells 2SC4916 for $5.08, MCM (800-543-4330) for $5.45, B & D (800-458-6053) for $6.54-- how much did that ECG2353 set you back?  When you HAVE to try a universal sub, check the HOT's case temperature right after running it, and be sure it is not running hot, before letting it out of the shop. A good HOT choice generally does not run too hot. QUESTION NO. P98-10:  How can I determine who the original chassis manufacturer of a monitor is by using the FCC ID# on the back of a monitor?Locate a link to the FCC data base and use the information on the back of the monitor to confirm source of origination. Database is very easy to use, just have to type in the ID info and it will come up with the material, if stored therein.The first three characters in the FCC# determine the true manufacturer.  You can identify them either by going to the FCC site at http//www.fcc.gov/oet/info/database/ead/  and downloading the ZIP datafiles of these three-character ID's, or else by using the FCC's online search engine at   http//www.fcc.gov/oet/fccid/.  Note that the same manufacturer

may have several different three-character codes assigned to them. The remainder of the FCC# identifies the individual chassis.  Theoretically, every time a manufacturer produces a new chassis, or even modifies an existing chassis, it requires re-certification by the FCC, and the chassis gets issued a new FCC#.  QUESTION NO. P812-7:  I have a Packard Bell 2020 monitor which has a brightness problem. The bright ness control has absolutely no effect at all. The control is an analog type of control and I have checked it  with an ohmeter, and it measures good. Someone told me it could be an open transistor or restor near the flyback. Has anyone seen this problem before?  I am not sure where to start looking.  Monitor is 15 months old.I was working on a lot of 2020 two months ago.  The common problem is no panel control, sync lost, will not start, buzz, etc,  I only changed epromm 93c56 and, for one only, I put a Proc Zilog z0861404psc.  You need after to put a shield ground on two parts, because they have a risk of static discharge(it is the problem).  Call Parts at LJ Enterprises .  The price for eeprom preprogrammed is about $10,and zilog $20.If there is a voltage on B+ around 50V then you should change IC I804(UC 3842).  Important, there are two IC UC3842 in this kind of monitor.   I804 is NOT in a main power supply. QUESTION NO. P824-3:  Sony GDM-20E01 20" computer monitor; has vertical smearing (bad focus) in about the middle third of the screen.  The smeared band is vertical in orientation on the screen.  "Focus 2" control starts to clear up the problematic area & then the pot reaches its end before it pulls focus in (clearing this section un-focuses the good areas though).  Bad focus voltages? Guns? Tube?Check the focus voltage and HV.  Focus should be roughly 10 to 15% of anode.  If this confirms then you probably have a bad crt. Also confirm proper B+.  If it is too low, the beam current, hv and focus will be affected.This problem must be in dynamic focus.  Mostly this failure is caused by IC404 on the Main-Deflection board. QUESTION NO. P812-11:  I have a GVC M1448L color monitor with a burned R386 (next to the TDA1675A) and an exploded C802 (at front of board).  Does anyone know the value of these parts?R386 is 10 ohms, and C802 is a 47 uF  35V electrolytic capacitor. QUESTION NO. P816-3:  Compaq Qvision 480P.  Raster gets progressively brighter until retrace lines are visible.  Does not seem to be the flyback.   Anyone familiar with this problem?  Quick answer would really be appreciated.This is a common problem with Qvision 200. You need to replace "brightness and focus block".  It cost about $80 to $90. Good Luck. QUESTION NO. P816-6:  MAG MX17S monitor problems. I found cold yoke plug joint which caused  horizontal deflection transistor Q503 (C3897) to short. After replacing it with NTE2354 I have a picture but pincushion circuit is not working at all. Picture looks like hourglass and pincushion trim pot is not responding.  Could someone please point to the pincushion circuit components that may be at fault?I found an answer to my problem.  I had to replace two darlington transistors Q909 and

Q506 (original 2SD799, replaced with available 2SD1409).  Pincushion control works now.  I still have a distorted picture and raster on the very top of the screen.  It looks like N-S pincushion problem -barrow shaped top of the screen only.   I cannot find any adjustments (trim pots or coils to compensate for it). QUESTION NO. P819-4:  I have a Wyse Model WY-60-02-02, that was showing H scan problems before dying completely. C205 has burst and R214 and C206 are burnt beyond recognition. Values for R214 and C206 would be appreciated, as well as pointers to any other potentially failed parts, (I have no schematic).R214 is 10 ohm 1/4 watt.   C206 is .22 mfd 100 volt.   Check for bad yoke. QUESTION NO. P729-3:  I have a CTX Monitor Model CTX 1760 DF.  The horizontal size is too wide and cannot be adjusted using the digital control. Even adjusting the horizontal size pot in the main board will not help. Could you help me on this problem?Try to remove dry glue in supply unit, and in main board (right front).  This glue goes to resistive when dryed, very common on this model.  No adjust on horizontal and pie crust on screen.  Resolder connector in supply. QUESTION NO. P729-4:  I am wondering why the damper diode of the IBM G70 monitor keeps shorting. A new diode (BY359F 1500) will bring it back to life, but only for a few minutes. The diode shorts, the power supply stops.  Could you tell me what the original diode for cr301 should be?  IBM G70 model 6544-403 part number 96G1870 FCC ID AN06544.Diode must be at least 2A 1000V.  Any diode less than that will blow. QUESTION NO. P86-1:  I have a 15" FS SVGA Monitor with some troubles.  I am having a little trouble figuring out who it is who actually makes it and how to fix it.  I have seen many monitors with this same appearance (an example would be the Princetons and KDS monitors).  This display says "VIDEAL" on the lower left area and on the rear panel the sticker says ASTRAL MICROELECTRONICS CORP.  FCC ID# IJEPV-564D PRODUCT# PV-1564A MODEL#  PV-5640 MFG DATE = DECEMBER 1996.  I am guessing that the trouble is in the high voltage section but I am probably wrong.   When turning it on, the power light comes on and there is a slight static sound (like the HV is coming up) but I can not feel anything on the display.   I have done monitor repair before , but have never done one with this "DIGITAL CONTROL CIRCUITS" getting in the way.The FCC number is your best indicator.  This number will tell you if the chassis is the same as that from another brand name.  It also is needed when dealing with brands such as AST, Gateway, or Packard Bell, that market different chasses, from different manufacturers, under the same model number. For example, a PB "1412SL" or "1512SL" can be made by several different manufacturers!  This makes trouble-shooting such models, or relying on "Tips Databases" for them, difficult.  In your case, the "IJEPV-564D" indicates this chassis came from Essex Monitor Corp., Taiwan, and is the same chassis as the Proview PV-564D.  With regard to your problem, first check if the CRT is a Samsung.  The Samsung CRT's in these chasses are notorious for going bad.  If the CRT is OK, and you are getting HV but no static on the screen, see if the CRT filaments are lit and the associated circuitry is OK. If they're not heating, the electrons that should go to the face of the CRT will never get emitted.  You might also check the 12 Volt supply.

 QUESTION NO. P730-10:  I have a monitor type Hyundai HM 421 . The problem is that I have a scrolling picture (from top to bottom).  I have already replaced TDA 1675A,TDA1180,NE555,74LS86,74LS156 but without any result. Can someone give me some tips?Check the signal cable for a cracked wire (Vsync). QUESTION NO. P81-1:  I have an Apple Multiple Scan 17 Monitor (M2494) which is overscanning by perhaps 50% both vertically and horizontally.   The screen geometry is fully electronic ie. no potentiometers.  The Apple literature that I have access to suggests complete replacement of the deflection board, this seems like an overkill.  Any suggestions or ideas would be appreciated.This is a "default" failure for the 2494!  Q510 is defective and must be replaced only by the original (FS10SM-16) 8-729-025-94. QUESTION NO. P83-6:  I am working on a Philips C2082 Monitor that reports 'HIGH VOLTAGE Fail' on its LCD. I checked flyback and the high voltage and the -200V that it produces come on very briefly after power-up. Then the voltage collapses.    Could it be the beam limiter circuit doing its work (not properly)? How can I locate the faulty circuit (components)? Also which brand is the HOT (THD 400) used in it?Check fuse 801 (solder type near flatcable to hv-box).  If it blows again, most likely the flyback is defected. QUESTION NO. P83-4:  I have a Packard Bell Model 2020 monitor that has no screen brightness. The control has no effect at all.  Pot measures good, picture is there and has contrast, but no brightness. Unit is only 14 months old.  Anyone seen this and can help?Check g2 and g1 supply, g1 can be too much negative. Check drive on RGB drive on CRT.If there is a voltage on B+ around 50V then you should change IC I804(UC 3842).   Important, there are two IC UC3842 in this kind of monitor.  I804 is NOT in a main power supply. QUESTION NO. P84-1:  I am working on a Daytek monitor, model dt-14xvb, fcc idewboc143xv.  Problem is no hv.  Power light go on regulator and capacitors arround the flyback and smps test ok.  I have six units with the same problem.Check the TDA1675A vertical IC.These 14" Daytek monitors seem to come up with this problem quite often.  Replace C8062.2uf @ 100v, C8082.2uf @ 100v and C824 @ 160v.  These capacitors are located on the primary of the power supply.I have repaired several with the flyback connnections pulled away from the land patterns. This is done when the flyback mounting screws on the OUTSIDE bottom of the case are tightened. To correctly suck all the flyback pins clear, insert the mounting screws and tighten the flyback to the PCB. Solder all pins and re-assemble as normal. This has happened on the last four Daytek monitors repaired for no HV.The Daytek dt14sni and dt14xvb are basically the same.  If you have one that will not power up at all usually c824 is bad a 1uf at 160v.  If the power light is red instead of green, check to see if you have about 10kv high voltage. There is a cap 100uf at 200v that may be bad.  There are two c812and c815.

 QUESTION NO. P726-6:  I have a Visa MC 8960 monitor which works fine, but when I turn off power I'll get a spot in the middle of the screen.  I've already changed some condensators on the video board but without any result.Suspect a fault in the "spot-killer" circuit. This is a circuit that is supposed to kill all the bias to the crts when powered off to eliminate this problem. QUESTION NO. P81-7:  I have an IBM 8513 that blew the HOT transistor after making a buzzing noise. When I replaced the transistor, the monitor has HT voltage but no longer has any vertical deflection.Prob the vertical output ic and associated rectifier and protect resistor{s}. Prob the ic failed causing an overload which is what caused the ps to buzz in agony before opening the fuse resistor.Check all power rectifiers coming off the flyback. Perhaps there is a shorted one which powers the vertical outputs. There may be a fusable resistor in series with the rectifier. Also check the electrolytic capacitor on that line too, as well as the parts in the vertical circuit. QUESTION NO. P726-4:  I have a NEC 4fg (jc-1531vma).  Someone has worked on this unit before and removed two parts.  Need to know values of Q-503 and Q-504.Q503 is a K699 and Q504 is a B536 with a heat sink. QUESTION NO. P717-9:  I need the horizontal/vertical scanning frequencies of the Samsung SyncMaster 15C monitor. Can someone help me?The 15GL Horizontal Frequency 30-62, Vertical Frequency 50-100, Max Pixels 1024x 768. QUESTION NO. P728-10:  I have an Applevision 1710, family model # M2935 which does not power up when video signal is supplied from Sencore's CM2125, there is no power on LED. Does this monitor need some type of adapter to power up?Sencore makes an adaptor #8 or #8f that will turn the unit on. QUESTION NO. P717-6:  We are looking for a replacement diode for D925 on a Micron 15fgx monitor. The number on the diode is BYM26C PH. Anyone have any ideas?BYM26C is a Philips rectifier, 600 Volt, 2.3 Amp, 45 Amp surge, ultrafast recovery (Trr <30 nsec), with soft-recovery characteristic.  The leads are thicker than usual in dia., and manufacturers may install them with long leads, to help radiate heat. If your Philips supplier cannot provide it, the closest US-type rectifier meeting these specs is 1N6628-JANTX, which Arrow Semiconductor lists for $8 each.  Or, if you wish to try a cheaper rectifier, HER306 has similar capabilities, but has a slightly slower Trr than these two. HER306 is listed by Mouser (800-346-6873) for $1.17 apiece.  QUESTION NO. P724-7:  I have a Gateway ( Sony ) monitor model CPD-17F23 that came in with a shorted horizontal output transistor.  I have replaced the transistor and the monitor will try to come on, but I only get about 25 volts on the collector of the HOT.  I have checked the other supplies in the monitor and they are all fine.   B+ 141 volts, I also have the 75v 45, +5 and switched 12 volt supplies.    Has anyone had a similar problem and knows what else is a common failure for this model?There are only a few components between the reg B+, primary of the FBT, and the HOT.

Check the B+ @ the primary of the FBT.  If good there then the coil in the FBT is probably bad.  If low there then problem must be further back towards source.  I should suspect the B+ is low to the FBT caused by some defect between it and the power supply. QUESTION NO. P722-5:  I have a NEC monitor with the model number of JC-1402HMA and FCC ID of A3D9MDJC-1402HMA. On the power supply board PWE-195, resistors R623 and R632 were burned beyond recognition.  I was wondering if anyone could please tell me what value they are supposed to be?NEC maintains a tech support page, with listings of the original parts for its JC-1402HMA monitor, at http//cssweb.nectech.com/Original/ms2/parts.htm.   According to that site, R623 is 5.6K, 5%, 1/4W, and R632 is 1.2K, 5%, 1/4W.R-623 is a 5.6k 1/4 watt and R632 is a 1.2k 1/4 watt. Notice that they are both sitting on pin 14 of IC602 which might also be bad stk 7404. Also check diode D610, transitor TR602 and resistor R624 (1 ohm 2 watt). The DC output at C1 will run anywhere from 53 to 98 volts depending on the mode the monitor is running in. The fixed output voltages at K1 and K2 are +85 and +26 volts respectively. QUESTION NO. P720-6:  I have a Dell Model D1726S-HS that all colors have faded, red is real light pink.  Focus and brightness looks good. Customer said this has progressed slowly.You should test the tube, preferably with the Sencore beamrite 7000 which checks low level tracking. This test when it fails indicates a "leaky" tube which affects contrast and colors - NO way to fix this problem. QUESTION NO. P720-9  MONITOR IBM 8515  I have replaced a fbt TLF71004D in the 8515-002 model and it worked correctly.  The same fbt on the 8515-022 and 8515-222 models do not work correctly.  Apparently the boards are the same, without difference.   I have tested more fbt and different models but without results!!   The fbt is not original, is a copy but works correctly on the 002 model !!   Both the model install a tlf71004d fbt. You should test the tube, preferably with the Sencore beamrite 7000 which checks low level tracking. This test when it fails indicates a "leaky" tube which affects contrast and colors - NO way to fix this problem. QUESTION NO. P623-9: I have an HP-1512sl Computer monitor with no contrast control. I have checked the Pot, its ok, I have followed the traces over to one of the two large I.C.s and suspect the problem is with one of the I.C.s CRT checks fine on Sencore CRT tester. Has anyone corrected this type of problem before?You should test the tube, preferably with the Sencore beamrite 7000 which checks low level tracking. This test when it fails indicates a "leaky" tube which affects contrast and colors - NO way to fix this problem. QUESTION NO. P630-7: I have two ACER 17" 7176i monitors, on one there is no GREEN, so the monitor looks pink, and on the other there is no RED, so the monitor looks Blue. I have checked the output transistors, and the reistors and caps in each color circuit, but have not been able to solve the problem. Any suggestions?If I am correct, this monitor has a microprocessor that controls the presets of RGB gain. On the processor board, there is a LM-324 in SMD that could cause this failure. The blue level

is adjusted at lowest in case of a defect opamp. QUESTION NO. P720-1:  I  have a CTX CMS 1561LR which was dead. I replaced the 2SK955 and the ZD101 (1watt) and the HOT. I checked R113 and found it to be alright.  Also WHERE is ZD102?  I had replaced ZD101 with 5.1V zener. Unit would not come up. I then read the reply to "What is ZD101" and installed 18V,1W zener for ZD101, now the unit "cycles" the relay (green led blinking away madly) at 2hz. Did I damage anything by installing the 5.1V zener, or where else shall I look?You say you replaced 2SK955. If the FET had shorted, it might also have damaged the 3842 PWM IC. And check resistor R114 = 0.39ohm for value.   ZD102 should be on the same daughterboard where you found R113; check values of the resistors and the diodes on this board as well.  Bad solder on this daughterboard, especially cracks on the pin connectors to the main board (or on the main board side) can also cause these problems, and need resoldering.  Of course, there might be a genuine circuit fault on one of the Power supply outputs, too.Replace the .39 ohm resistor.  I had a similar problem that fixed the flashing LED. QUESTION NO. P721-5:  I am working on a Compaq model #470ap with a burned resistor at location# R201.  Does anyone know the value?R201 = 1 ohm,1/2 W QUESTION NO. P610-1: I am trying to find two Philips caps for an Apple monitor. The cap values are 11nf @2000VDC, and 5n6@2000VDC. I've tried Newark and other parts houses with no luck. Any suggestions? I can't give you a precise answer, because the information you posted was so scanty.  Philips makes SEVERAL lines of caps with  5.6 and 11 nF values at a 2KV rating, both ceramic disk and film types, all of which are intended for various monitor functions.  You didn't post the Apple Model number, or cap location numbers, so no help there.  But it is my guess that you are looking at two rather large radial box film caps.  If so, these are polypropylene film caps, NOT polyester, and are snubbers specially constructed to handle fast dV/dT pulses.  You will NOT be able to sub these with polyester or ceramic disk types, they would dissipate too much power, and melt or self-destruct. There may already be a Philips type number on the cap, something like KP/MMKP376 or MKP378.  Or if this has faded, or was blacked out by the manufacturer, note the exact dimensions and style of the cap. With this information, go to the Philips Passive Components website at http//www.passives.comp.philips.com/  , download the data sheets, and find the multidigit Philips catalog numbers that match your caps.  With those part numbers, a parts house or a Philips supplier may be able to help you out, or suggest an equivalent. Cornell-Dubilier is one North American manufacturer that makes polypropylene snubber caps with fast dV/dT ratings; Mouser Electronics is a distributor of their line. QUESTION NO. P76-2: I am looking for a supplier for the 11nF and 5.6nF 2000Volt philips caps used in a Mac monitor.  I have tried several Canadian suppliers to no avail. Can I sub these with ceramic disc caps or do have to have the polyester high temp caps? I can't give you a precise answer, because the information you posted was so scanty.  Philips makes SEVERAL lines of caps with  5.6 and 11 nF values at a 2KV rating, both ceramic disk and film types, all of which are intended for various monitor functions.  You

didn't post the Apple Model number, or cap location numbers, so no help there.  But it is my guess that you are looking at two rather large radial box film caps.  If so, these are polypropylene film caps, NOT polyester, and are snubbers specially constructed to handle fast dV/dT pulses.  You will NOT be able to sub these with polyester or ceramic disk types, they would dissipate too much power, and melt or self-destruct. There may already be a Philips type number on the cap, something like KP/MMKP376 or MKP378.  Or if this has faded, or was blacked out by the manufacturer, note the exact dimensions and style of the cap.  With this information, go to the Philips Passive Components website at http//www.passives.comp.philips.com/, download the data sheets, and find the multidigit Philips catalog numbers that match your caps.  With those part numbers, a parts house or a Philips supplier may be able to help you out, or suggest an equivalent. Cornell-Dubilier is one North American manufacturer that makes polypropylene snubber caps with fast dV/dT ratings; Mouser Electronics is a distributor of their line. QUESTION NO. P71-6: I have a Premio (made by sceptre) model 566 PN:P-514ca monitor. I am getting no high voltage. HOT and flyback are both OK. Power led does change from amber to green when signal is applied. Any ideas?Check the horizontal driver transformer drive transistor, and associated components. Confirm there is bias at the collector of the drive transistor and output. Confirm there is horizontal drive signal to the driver and output.  Check for any type of unusual loading in secondary of flyback, including shorted yoke or bad crt.  QUESTION NO. P617-10: I have a Dell P1728U monitor here that had a shorted diode (D954). After replacing the diode, the vert IC blew, and I cano't read the number. I suspect that the vert IC was shorted causing the diode to go.. With the vert. IC taken out, the monitor comes up but the LEDs on the contrast and brightness controls flash and the vert. size led is on solid. Can anyone tell me what the part # of the vertical IC (IC401) is?IC401 is a TDA2006 QUESTION NO. P617-5: Je cherche la référence exacte du circuit noté dans mon cas KA2139S sur un écran Diamond 15pcs.Ce circuit est apparement le préampli vidéo. Le circuit KA2139S est effectivemment un préamplificateur RGB pour écran. Il est fabriqué par Samsung Semiconductors. Vous en pouvez obtenir la "datasheet" en format .PDF (Acrobat Reader) à www.sec.samsung.com QUESTION NO. P630-8: I have an NEC monitor, ModeJC1575VMA, when powered on the HV is ok, I have a green LED and normal raster when the screen control is turned up. The problem is a "NO VIDEO" symptom. Normal video signals enter the LM2405 I.C. on the video P.C.B but no signal is present on the CRT cathode pins. LM2405 is a triple CRT driver for R,G, B.  I take your comments to mean that there are three video inputs (not blanked) going in to pins 8,9,11, but none are coming out (at pins 5,3,1).  This IC is open-loop and fixed-gain, with independent amp circuits for the R,G,B signals.  So, if NONE of these signals are coming through, either the IC is bad, or one of its two supplies is down. First, check that you are getting Vcc at pin#6 and Vbias at pin#10; these should be at the very least +60V and +8V, respectively,  relative to ground (pins 2,4,7).  More typical operating voltages are +80V and +12V, respectively.  If either supply is below the minimums, check if there is an internal short in the IC at either of those two

pins, if the bypass caps off pins 6 and 10 are good, or if either of the two supplies is not functioning upstream.  If both supplies have good voltages, and their bypass caps are good, the IC itself is probably gone.  QUESTION NO. P630-10: I have a Sony CPD-1320 monitor in the shop which the customer complains that it works fine in DOS, but won't sync in Windows. I don't have that problem on my computer. It works fine in DOS and Windows at 640X480, but at 800X600 the image is shifted left, and at 1024X768 the picture rolls. There are no user controls. I've changed every IC on the main board and checked all caps. Any suggestions?You have been beating a dead horse. The Sony CPD-1320 monitor was designed with a maximum resolution of only 640 by 480, 60 Hz. This is probably your customer's problem too. QUESTION NO. P616-6: I have a Monitor ACER 7176N and R458 is burned. I need know the value of R458.R458 = 2.7 ohms. QUESTION NO. P618-6: I have a viewsonic 17gs dead it uses a surface mount board. Any ideas on where to start?Do not be intimidated by all the smd devices. Check out the power supply and regulator as well as the horizontal output & HV. Unless the unit took a major overload the probability of damage to smd devices in minimal. QUESTION NO. P618-1: I was working on a Gateway 1776Le 17 inch with no video. Replaced R177,C120,C123 andHOT with an ECG 2354. R181 and Q116 checked O.K. Monitor came up and worked beautifully for about 45 minutes then the screen started closing in horizontally until it went out. HOT is shorted again and the monitor just clicks now. Did I use the wrong HOT or could something else be killing it?Did the fbt get really hot before blowing the transistor, then the fbt is probably bad, or you have a severe overload in the derived supplies. Otherwise check the regulated B+ to make sure it is not to high, running on a variac at reduced voltage may help diagnose.Those parts which you mentioned have a nasty property: if one of them goes bad, that can then take out any of the others. But one more common-failure part that you didn't mention needs to be added to that list: L105, a somewhat tall, 4.5 mH loading coil connecting to the B+ input of the flyback. Usually when the HOT shorts, L105 gets cooked, and the bad L105 can then do in new HOTs, etc. Replace it if it looks slightly discolored or bubbled, or rings badly, or even on general principle. L105 is Mag Innovision (800-827-3998) part# T*I-281-103-UO, and suppliers like LJ Enterprises, MI Tech, CCS, et al., may carry this coil too, roughly $12. And then go back and test all those other parts once more, since you've had yet another failure. Aside from L105, if bad B+ regulation is giving the HOT excessive voltage, see if Q116 is leaky now, or if C334 or D116 or the flyback has gone bad. The usual Q109 transistors used in these Mag units are 2SC4747, 2SC4924, or 2SC5129.  QUESTION NO. P616-9: I have an AST Vision 5L that has lost horizontal widht and pincushion control. HWat are the most likely culprits?Since you did not post the unit's FCC number, I do not know the true manufacturer, so I can

only say that IF your Ast 5L is one of the Daewoo versions of that model, possible culprits could include IC901, and diodes D502 and D503.  QUESTION NO. P69-1: I have a NEC monitor model 3FGX which had a focus problem so I changed the Flyback. The monitor seemed fine for a while then it would not turn on anymore.Check out the HV-adjust pot VR516, a silicone-sealed 20K ohm pot near the flyback. These are factory-preset for each individual unit (hence the silicone), so your new flyback may need that setpoint changed. These pots can also go bad and cause shutdowns. QUESTION NO. P64-4: I have four CTX VL400 monitors that keep shorting the HOT , the flybacks are ok. If those VL400's have cap C722, a 47 uF/50V electrolytic, near the HOT, that cap commonly gets bad ESR and affects the HOT. With that many units down, some may also need to have Q406, Q407, and FET Q410 checked for leakiness or shorts.  QUESTION NO. P68-11: I have a CTX CMS 1561LR which was dead. I replaced the 2SK955 and the ZD101 (1watt). Now the unit stays on for about 90 sec. I checked R113 and found it to be a 100 ohm resistor. Also what is the value of ZD102?There seems to have been a typo in your earlier response. CTX service dept. had issued a recommendation that ZD101 be upgraded from the original 18 Volt, 0.5 Watt zener to a 18 Volt, 1 Watt zener, to avoid fuse failures. ZD102 is 5.1 volts at .5 watt. QUESTION NO. P527-6: I am working on a MAG DX700T - shorted horizontal transistor 2SC5048. I need value for R173 which is unreadable.For the Mag DX700T, my notes say R173 = 1 ohm. QUESTION NO. P61-6: I have a Dell D1528LS with no raster, HV is 26Kv, Heater is 6.3, but G1 is about 20V more negative than it should be after doing comparison to a working unit. It appears that the processor could be holding the tubecutoff. If this Dell 1528LS is a Lite-On unit, with the Zilog Z0861404PSC processor, that IC is known to give problems, and shutdown to black is one possible symptom. Sometimes freezespray or heating can reveal this IC as a culprit. These IC's have a number stamped on the chip ("Zilog xxxx") indicating the programmed version. So a replacement Zilog (~$20) must be compatible with that version, or you won't have access to control functions like pincushion adjust, or won't sync, etc. Try LJ Enterprises (800-627-8755) or Partronics (800-232-3055) for help on this aspect.  QUESTION NO. P61-5: Goldstar CMT-4568 Chassis NC-06X1 No verticle deflection. Output from IC02 pin 6 is flat +5v DC. Is the problem likely to be with IC02? If so, can you assist with e replacement cross-reference. The chip is labeled NEC D6104C. The full number for this NEC chip is UPD6104C. Try Union Electronic Distributor, Illinois (800-648-6657) or MCM Electronics, Ohio (800-543-4330) for this IC, both had listed it in their stocks. QUESTION NO. P527-4: I have a nec multi sync model jc 1531vma<4fg> bad side

pincushion. The adjustment does not work. Has anybody come across this problem?The common problem that causes this symptom is that C561 = 470uF on the main board can leak electrolyte, damaging traces on the PC board. Remove the cap and check underneath: if this cap leaked, you'll need to clean the board well, check all nearby traces carefully for damage, and to jumper any damaged traces. Even with no loss of continuity, leakage onto the trace from the wiper arm of pot VR403 to pin# 8 of board# PWE317E can actively cause problems, so you may need to actually CUT that trace at both ends, and jumper between the cuts. Note, the leaky cap may actually test good, but replace it anyway with a 50V cap. Cap C557 can also get leaky and should get checked, too. A bit of conformal coating or lacquer on the PC board after cleaning well can be a future safeguard. Secondarily to this problem, if it still will not adjust, and you're sure you caught all the damaged traces, check IC4E2 and IC4E4 on board PWE-317E, check that there is 53.5 Volts across resistor R409 on the main board, and check C523. QUESTION NO. P511-9: I have a CTX model 1760df that has a problem powering at the startup. It takes awhile before it powers good. Try replacing IC104, 4n36; IC101, tda4605; R129, 47k 1/4-watt; R172, 100k 1/2watt. Also check for bad solder connections in the power supply.  QUESTION NO. P520-3: I have a viewmaster CA 1414VL that i believe might be the same as a KFC CA 1414VL. I have found that IC  U502 has had the top blown off it and that R527 is burnt out so that I cannot identify either component. Can someone identitify th part number of the IC and the value of R527?U502 is a UC3842 which crosses to an NTE 7096. R527 is a 1 watt .22 ohm flameproof resistor. QUESTION NO. P518-2: I have 2 NEC 14" multisync 4FG model # JC-1531 VMA monitors with the same pincushion problem. The screen has good clarity and brightness and switches to all modes but the sides of the picture are concave )(.Check C561 470uF/25V could be leaking on bottom replace it with a 470uF/50V 105 DEG.C. if it still does not work check IC552 LM2940CT 12V 1.5-AMP regulator. QUESTION NO. P514-5: I have a Packard Bell mod# PB8515sv BPCS#010201001 FCC ID# BJMCM15VD which looses the screen size/position controls after it is on for a couple of hours. If it is run in a cool enough area the problem does not occur. I replaced the High Voltage regulator and it seems to be working fine. QUESTION NO. P417-1: I am working on a Viewsonic Model 5 computer moitor that came in for vertical collapse. after troubleshooting found defective vertical out ic. replaced, now have picture with terrible found over, can any one help.Determine the reference designator (ic number on circuit board) for the vert IC and change out the caps that have the same first number in their designator. Generally, the caps closest to the heat-sink are the ones to go bad first. When replacing a vert IC, it is a good idea to replace these caps also, as they are often the souce of the failure anyway.  QUESTION NO. P430-10: I have at several times seen similar 20 inch monitors under the brand/models of PHILIPS.FSR871CV, DIGITAL.PCXAVF4 and

COMPAQ.480/480P/481. All give the same symptoms, that is a message on the LCD "HIGH VOLTAGE FAILURE". Apparently the "EHT GENERATOR" a very expensive and hard to get tin box containing a FBT and a few other components will fix the problem. I do not believe that the actual FBT is faulty, as in some cases the symptoms are intermittent. FBT's usually are not intermittent, and either burn, short out or work ok. Does anybody out there know the "real" info or story on these models?My experience with these models wasn't the flyback causing the problem, but the voltage multiplier/focus divider. This is usually noticed by a flickering screen, intermittent focus problems and intermittent video. These units are made by Philips for Compaq (Qvision 200) and other companies. The flyback is easy to order from CCS, but I have had a difficult time trying to get the multiplier/focus module. I contacted Philips (which is an expensive 900 call) and was told that they don't have the module, that it is only available from the company the monitor was built for. I then contacted Compaq, they denied being able to provide any parts, that Philips would have to provide the part. Possibly someone else may know who sells this module. QUESTION NO. P430-8: I have a couple of Samsung monitors Samtron SC528UXL sold as AST Vision 5L. There is very dark image or no image at all. Flyback seems to be working OK, filament draws about .6 A. It seems to be problem with the crt. Does anyone have similar experience or suggestion ?It is commonly regarded in the monitor repair circles that these samsung CRTs are not good. They lose emission often. A CRT tester will show if this is the case. QUESTION NO. P56-6: Pionex VM 1491H lost vertical scan, several resistors burned, need values of R464,R465.There are two Electrolytic caps in the power supply that cause over voltage which damages the Vertical output circuit. R465 220 ohm; R464 2.2K ohm. Caps that cause the problem are 1 uf and 10 uf near the SMPS transformer. FYI: there are several versions of this circuit board with different numbers for the components. QUESTION NO. P56-7: I am working a a Compaq 461 14" monitor (ADI SM-5514N). It was not producing any video. I replaced the Zilog IC and I now have video back. The problem is it will not sync on all video modes. It will sync on 1024x768 I or NI but not at 640x480 I or NI.There are several versions of CPU chip. Be sure you have read the "Rework" instruction sheet to verify the correct modifications have been made.  QUESTION NO. P56-5: I have repaired a CTX1461 monitor, only to find that the original cause of the failure is an intermittant open within the power supply transformer. The failure took out 3 components, the switcher fet, zener, and shunt resistor. All replaced and the unit works. The problem is that under a small amount of vibration a transformer winding opens. Where can I buy the xfrm #47S00-0490? CTX is out of stock and said to call back in 3 weeks. Any ideas?Most of the problems with this unit are cracked solder joints on the "Daughter" board. This problem is very common with the 1561 & 1461 CTX monitors. QUESTION NO. P56-4: I am repairing an ADI monitor model SM-5514B. The horizontal

drive transistor gets its drive from LA7851. But there is no voltage on its collector. Therefore the monitor is dead apart from PSU. Tracing the print brought me to two devices which appear to supply/control power to hor.drive transistor. They look like small signal transistors, but I have no idea what they are. They do not measure like transistors at all. Reference numbers are Q806 and Q807. Q806 is marked as NIA4M/K327C Q807 is AIA4M/K325C. If anyone knows what they are or has a circuit diagram to suggest how hor. drive transistor gets its collector supply this help will be appriciated. Q806 and Q807 are NEC digital switching transistors (AA1A4M = NPN, and AN1A4M = PNP), and will not test out like typical transistors. Before replacing them, first check for the "sync for power" output signal from that little CPU-type board, which goes to Q806, Q807 to switch the B+ for the HOT. If that signal is not there, you are in shutdown, and your problem is with this CPU board. But occasionally those digital transistors do go bad. The following data should allow you to check out these transistors. Both transistors are 50 Vceo, 0.1 Amp, 0.25 Watt, pinout ECB, and have two internal 10K resistors that form a voltage divider network. One resistor goes from the base pin to the base of the transistor, and the other from the base to the emitter pin. This voltage divider on the base increases the voltage needed for driving the transistors, and also creates a 20 Kohm resistance path between the base pin and emitter pin, even on working units. If you DO need new digital transistors, a sub is NTE/ECG 2355 (NPN) or NTE/ECG 2356 (PNP).That device is a digital switch, ECG 2355. Your problem is not likely with those, the drive signal comes from the CPU board. The CPU is frequently the defective component. QUESTION NO. P430-2: I have a SGI monitor model number cm2086a3sg. Is this a multi sync monitor?Both revisions C and D of this monitor are listed as fixed frequency, analog, sync-on-green, not as multisync. QUESTION NO. P429-3: Vertical deflection failure, need values of R465, R466 on 1992-11-17 Anco Monitor board 1491H/1492H sold with Pionex 486/25.R465 = 270 ohm and R466 = 10 ohm. Bad power supply regulation can burn these vertical components, so with these two resistors burnt, better also check the values and/or ESR of the following: R392 = 100 or 120 ohm; C411 = 1uF/50V; C611 = 1uF/50V; C612 = 10uF/100V; C731 = 47uF/160V; C741 = 10uF/100V; and check the vertical position adjustment pot (1K ohm pot) for damage. QUESTION NO. P428-3: I came across a computer monitor I've never heard of before. It's called a "loop monitor". It is non-responsive to incoming video. It has an input that says "signal TTL" which looks like a svga input and a second input "signal analog" that looks like an older cga connector. Any repair data on this monitor or it's real maker?These Loop monitors were sold in Computer Shopper in the early '90s. They MUST have a special video cable. They will work with the "Sony" type svga 9 pin cables. QUESTION NO. P428-8: I have a MAC 21 inch monitor with Horz problems. I have replaced the transistor V104 and resistors R113 and R109. The monitor "fired up" for a second and then blew the parts out again. I do not know where to locate: (a) a schematic for the M3502 family (b) special chassis parts Can anyone suggest a cure or source of info for the monitor?

Besides the components you mentioned having replaced, you probably need to replace snubber caps C106 (0.0056 uF/ 2 KV) and C108 (0.011 uF/ 2 KV), connected across V104. These are typically Philips caps, and are usually bad in your situation, especially C108. It is also a good idea to check C121 (10uF/63V), C124 (10uF/63V), and C138 (33uF/16V). QUESTION NO. P428-1: I have an Nec JC-1539VMA that has an orange power light, no high voltage (it only draws about .05 amps of current), I've checked most of the power supply components but can find no bad parts. Does anyone have any experience with this one?These units are notorious for having defective IC881 microprocessors, Toshiba TMP87CK42N-4147, which mimic power supply problems when bad. NEI (800-659-3186) or CCS (800-356-1227) may have this IC, but it is pricey. QUESTION NO. P330-6:  CTX 1451 monitor that has burned several parts beyond recognition. I am looking for the values of R119, R112, and ZD101.I have looked in a CTX 1451 for you and have this info. R119 = 33k 2 Watt R112 = 1K .25W ZD101 ? only found ZD 102 = 18V 1 watt Zener. QUESTION NO. P417-8:  Toshiba 32G90 which will not startup. The power LED blinks on/off about once every second. After awhile, the set will turn on and work fine from then on. If the cycling on-off gets faster (say over 3-5 min.) look for a 330uF/16V cap near the power xfmr. QUESTION NO. P325-10:  IBM G70 which is completely dead.  By probing at the SMPS I can see attempts to start but nothing happens. HOT measures ok.Check the diode CR210... (can be replaced by BYV29-500). If it's ok, then check CR112, CR122 (can be replaced by 20V zener). If replaced, both diodes must be replaced, and flyback-tranformer must be adjusted . Also check Q101, Q102, R103 and R104. QUESTION NO. P318-3:  Gateway CS1776LE Monitor that went dead. I replaced PS tranny, HOT and Q116, plus many electrolytics just in case. The PS runs ok with all correct voltages.HV comes on and immediately shuts down. Relay RL101 kicks on and HV switches off. Relay drive comes from a daughter board. Does anyone know why it is supplying the command to switch the relay off? How do I fix this?Adjust xray and see if your monitor will stay on, and if you have a reduced width you need to replace c134 .0075uf @1600v. Also checkc120,c123 and L105. QUESTION NO. P415-5 : Packard Bell 1412sl dead. I have had little luck with p-bells due to the board mtd to the basemaking testing difficult had some that seemed to draw 1/2 power ~20 watts no hv this one dead Common points to check?Suspect the electrolytic capacitors in the vertical circuit. Probably the cause of the original is failure.  QUESTION NO. P415-6: Viewsonic 5 computer monitor that had vertical collapse. I found a defective IC202 vertical out ic. I replaced the IC now I have a picture with severe vertical foldover.

If this ic you replaced is the vertical amplifier. Then check the electrolitic caps around the Ic . I have had this IC replaced with a different Manufacters product. Some times the spaecs are so close that changing this chip will solve your problem. QUESTION NO. P311-3:  Several Daewoo 17" monitors, mod# CMC-1701M2. crt pcb does "electrical dance". The power supply goes crazy (switching} but checks ok. hot ok. All diodes ok. Suspect flyback?I have encountered the same problem many times. As much as you do not want to hear it the Flyback is the only answer! QUESTION NO. P48-7: CTX CMS-1461 monitor with a problem. The screen is shifted horizontally and cannot be adjusted to correct position. By shifted Horizontally, I mean that it starts in the center of the CRT and wraps around to finish the image so that the right half of the image is on the left half of the screen and vice-versa. The monitor would not work at all initially. This problem was traced to bad solder joints from a previous ?repair? or attempt to repair. I have since replaced the LA7851, several capacitors and diodes to no effect. I suspect the HOT is fine as aside from being shifted the picture is fine.Anyone have any ideas as to what to look for? Anyone seen this condition before?I have no personal knowledge of the horozontal shift, however I do recall another tech in our shop having the same or similar symptoms. I believe the solution was an incorrect sub or something related to the horiz. output. If this does not help resubmit question and i will specifically ask him.His trouble was only couple of months ago. I try to review this board at least once a week so would answer fast. QUESTION NO. P330-9: Sony KV20TS20 which has a problem in the Horizontal circuit. The horiz out keeps blowing after about a week. It does not run hot or anything but R605 Keeps opening. So it does have a heavy short in there when it does go. Anyone run across this before?Replace the horizontal only with original sony part subs will not last. QUESTION NO. P49-8: J'ai un Packard Bell modèle 2020 qui au bout de 30mm se coupe.Une idée?This question is the same as P1217-9. Look in the FAQ [In french] Il y a deja une reponse a cette question sous la reference P1217-9 Regarde dans la liste des reponses QUESTION NO. P326-3: Epson monitor model # MCH-4095E with 9 pin "D" input connector. Monitor is selectable mono (blue or amber). Need to know connector pin assignments and mostly the type of PC video driver card to use. FCC ID #BEJ9QKMCH4095NPin assignment for a monochrome 9-pin D connector are:1, 2: Ground3, 4, 5: not connected6: intensity control (contrast)7: video signal input8: horizontal sync.9: vertical sync.Video monochrome cards usable are:MDA (monochrome display adapter) HGA (Hercules

graphics adapter) -Some CGA (Color graphics adapter) and EGA (enhanced graphics adapter) cards that have a switch mono-color can also be used. QUESTION NO. P48-6:  CTX 1451C that has D402 shorted "actually it blew in half and I do not know the part number" its a physically large diode on a heat sink in horz section. I replaced with another large diode just guessing at the value anyway it came up but is drawing about 1.5 amps current and has a loud hum. It also had a pincushion problem which was Q404 "A1015", I was checking parts and turning it on periodically and then d402 shorted again. Does anyone have a fix for this one or at least know the right part number for d402? It looked like 3TH from what I could make out. Two rectifiers are made that start with "3TH", Toshiba's 3TH41 and 3TH41A, both in 8 mm long by 6 mm dia. packages. These are rated for 1500 V., 3 Amps, and are fast recovery types (<1.5 usec for 3TH41, <1 usec for 3TH41A). Unless your substitute rectifier for D402 met these specifications, that could be one source of your problems. QUESTION NO. P47-11:  Gateway Cs1024NI2 monitor original complaint was display too dark. I found R241 burnt beyond recognition anyone know it's value?R241 is 20 ohm, 1 Watt. If that one is gone, then you had better also check ZD202 = 20V/1W zener; R325, R335 = 33K ohm; R331 = 91K ohm (must be exact value, no higher); caps C315 and C316. R241 and ZD202 usually blow from excess voltage, often due to one or more of those others being faulty. QUESTION NO. P310-5:  Gateway 2000 15" Vivitron monitor made by Sony (model CPD-15F13). The unit powers up and the green power LED comes on for a few seconds. The power supply sounds like it tries to start up again after a few seconds and then both the amber and green LEDs flash with no video. I had a similar problem which was resolved by resoldering the middle section on the main board. It seems to be caused by the fixture holding the monitor to the base rubbing against the main board damaging/scratching the joints/print. Apparently this problem is a known design fault.The above answer led me to the problem source and gave me ideas for correction.  I was a bit hesitant to just start resoldering the fine traces on the back of the circuit board, so I did the following and it worked for my monitor:  STEP 1 - Using a pencil eraser burnish the traces that have been damaged by the center support piece of the plastic cabinet bottom. You will be able to follow the location of this brace on the circuit board fairly easily. Some of the traces appear to have been spread and scraped, exposing the bare metal and leaving very small metalic "lint" between the traces, which could cause shorting. Once this "lint" is clean up and blown away inspect for any broken traces and resolder.  I did not have any broken traces.   STEP 2 - Using foam sheets make additional supports at various places around the board.  These supports are to keep the board and the cabinet base from contacting each other.  Make several, but do not block the free flow of air. Pay particular attention to areas on either side of the damaged traces. QUESTION NO. P325-6:  Sceptre monitor, model #H566, PN:P51, which will not sync on 640x350 or 640x480. On these modes I get squashed video at the top 1/4 of the screen which resembles a video IC problem. All other modes work fine. I suspect the TDA9103 IC but I would like a second opinion.

Sceptre units often have problems related to bad TDA9103 IC's. One symptom these IC's cause is loss of sync, esp. in the lower modes; another is pincushion. Usually, the IC's are worse when hot, so see if freeze spraying the IC makes a difference. Also, if the AGC memory cap off pin# 25 of TDA9103 is even slightly leaky (0.1 uA), AGC function is not reliable. The AGC re-establishes vert. amplitude after freq. shifts, so you may wish to check that cap (typ. 0.47 uF) for leakiness with a reduced vert. height symptom; replace with a low leakage cap. QUESTION NO. P35-2:  Two Acer Acerview 34T Model 7034T monitors that require Flyback Transformers. The part # on the Flyback is 19.70016.001. I cannot find any reference or cross reference to this flyback. Is there a source for these or a cross reference or substitute?Call Component Technologies. Their number is 1-888-flyback. QUESTION NO. P330-8: Dell Mdl D1727S-HS SVGA monitor, horizontal problem. FCC ID: A3LCMH737. High voltage comes up but not measured. The image on the screenis only 2" wide from top of the screen to the bottom. The video is all there inside this two inches, ie; you can read some of the characters. The sides of the image are straight not pinned. The dc power supply voltages were checked and are ok. The vertical shift and size seem to change in the image but the horizontal shift and size doesn't change anything. IC201 (uproc) has horz sync going in and out, also the horz size output from the chip is changing the duty cycle. Horz sync is then fed into a sync processor IC401 a TDA9103. When changing the horz shift or size, nothing changes on the horz sync out pin. The output is a 50% duty cycle square wave that doesn't change at all with shift or size adjusted. The collector of Q407 is 400vp-p. I have checked everything in the horz circuit and have changed the TDA9103 but cannot find the problem.I had a problem on a 17inch identical to yours. I found that the hot was breaking down. When I pulled the old hot out and compared it to a new one it was very obvious using a curve tracer. I hope that helps.If I read you correctly, the horiz. output of the TDA9103 (pin 20 or 21) is pinned at its maximal duty cycle (50%) regardless of input. This duty cycle level is controlled by a DC voltage to pin# 2 of the TDA9103. That voltage must lie between 2 and 6 VDC (assuming pin# 5 = 8 VDC) to be legal; 2V gives minimal duty cycle, while 6V gives maximum (50%). Try monitoring the input to pin# 2 and seeing if it is within legal limits, and if this DC control voltage can be varied between these limits. Assuming the TDA9103 is functional, it sounds like that pin is stuck high, and so tracing back from this point should lead to the culprit. QUESTION NO. P323-5:   I have been getting a few monitors in the shop that have problems when changing modes though.  I have bought books, tapes and software on monitor repair. Still no solutions. Since this seems to be generic to all makes there must be some tips someone can give me in troubleshooting these sets. The symptoms typically are as follows: VGA mode will sync and will be of the correct size. 800/600 will/will not sync, or is off center and squeezed in a little horizontally. 1024/768 will/will not, sync or may/may not be centered or sized correctly. Most printed materials and tapes on monitor repair give examples that are pretty simple problems and no examples of odd or tough dog problems.

One thing I find in the area where you're looking, the line sync. In the case of vga the line (horizontal) oscillator runs at a different frequency than in svga (higher). Think of monitors like tv's with the rf and if ripped out. They are a world wide standard which is useful. Your fault sounds like it may be in the sync or osc. timing circuit. I cannot help anymore than that, but I know it fooled me when I first saw it. Think of it like a dual standard tv. Ie 625 / 525 lines.You may not be aware that all vga monitors will sync in on your basic 640x480 but not all are created equal. A lot of monitors are nothing more than basic vga,not supervga. A good indicator is if you see adjustment controls inside that give you individual controls on different freq ie..vheight and hpos.that allows you to adjust all your screens to be centerd when switching from one mode to the other. A lot of times you will find that you can get pictures on some monitors that are not designed for it but the syncs will be off. I hope that helps. QUESTION NO. P330-7:  Trying to find any info. on a 27" data grade monitor made by a now defunct company named "frox". It was originally part of an elaborate and very expensive tv/cd/a/v system for home entertainment back in the 80's. To the best of my knowledge they went out of the business.Check FCC Data for mfgr info. It should have FCC ID number located on unit, prob near model number tag. I have seen monitors with the Weltrend Chips having thermal problems. This seems to be a pretty common problem with Weltrend WT80XX chips, especially in monitors that have those chips mounted up under the CRT. With these chips mounted there it is hard to get a sufficient amount of air flow to cool them and sooner or later they seem to break down and become thermal time-outs for sync. The SuperCom is just such a monitor, and the AOC is a close follower. There are probably more than I realize that have this inherent problem. Recently I bought some monitors just to have as loaners. Among these was a SuperCom ST1496 (popular with this problem). I decided that Weltrend should be putting heatsinks on these chips and wanted to see the effect a heatsink would have. I cut a piece of 22ga aluminum into a rectangle approximally 1.5" X 2.375", cut fins into it on both sides, (on the side close to the CRT these were shorter than the ones on the side toward the back of the board), and used small needle-nose pliars to twist the fins to a 45 degree angle. The center of the heatsink I left wide enough to just fit on the surface of the chip, making sure the fins would not be too close to the pins. Then I used JB Weld and mixed enough to cement the heatsink to the WT8042.I have left the monitor on for as much as two and one half days solid with no loss of sync, even after this chip had already been weakened by the heat and was loosing it's sync after about an hour. I would have either installed a new chip or attempted this repair only after discussing it with the owner had this not been mymonitor, but I was curious and had nothing to loose.I might even try mounting a heatsink using this technique on a new chip sometime. JBWeld to those who haven't used it is an epoxy base filled with steelpowder. Maybe they make an aluminum filled epoxy (more conductive). QUESTION NO. P32-7:  Acer View 44, (virtually identical to the View 34T) that has a strange problem.  Periodically, the picture fades out to black. Hitting the monitor on the

side sometimes brings it back. Sometimes the picture looks washed out and overdriven. I have tried touching some of the most suspect solder points, but it would help if I had a starting point. Check TRC heater voltage (6,3 V., pins 3-4 of TRC socket counting counterclockwise) when picture goes off; if there's no voltage but it appears when picture comes back, look for bad solder joints tracing the circuit backwards to the power supply. Usually, the 6,3 V. tension comes from a single diode-electrolitic cap circuit at the secondary of the power supply transformer. QUESTION NO. P319-5:  Several Compaq model 420 VGA monitors with no vertical sync. HV and signal are good (you can see the squished text on the horizontal line). I've heard is was a major problem back in early 90's with the 420 models. Has anybody else had the same symptoms? What IC's, caps, etc. should I be checking?Yes the Compaq 420 had this problem quiet often. I have fixed several dozen of them with this same symptom. You usually have to replace one IC and one resistor to fix the problem. IC-202 (TDA 1170S) and R-215 (8.2 ohm resistor). R-215 will probably be burnt. In a small percentage of them you will also need to replace R320 and the diode at D306. These are both near the flyback transformer. The resistor will read open and the diode will read as shorted. QUESTION NO. P36-9: Does anyone know what test equipment is nessasary to program the newer type monitors to set crt tracking for greyscale on monitors without individual potentiometers on the crt video board and where to purchase it?The only monitors I have seen without internal color controls have digital controls for color drive. These controls are accessed through the main menu on the front panel. QUESTION NO. P314-3:  Samsung SC-428PTL.  There is pincushion and the horizontal size is too big. It cannot be adjusted with the potentiometers for pincushion and horizontal size. Does anyone know the solution for this problem? Suspect possible bad connections in deflection circuits, esp near the capacitors in the horiz. Also check any PCC correction active devices for proper bias voltages and signals. Shorted or open diodes in damper circuits for pcc also may be a suspect. Leaky or open ringing capacitors in yoke supply [ horiz and vert] can cause pcc. Excesive width probable incorrect supply voltage or open ringing cap in horiz circuit. Coupled with the PCC problem I would suspect open or leaky components. QUESTION NO. P311-4:  Auroravision SM583 15" monitor where the image shudders everytime the case is lightly tapped.  Read somewhere that this is a common problem with this model.Check crt board/and or main board for loose solder connections. QUESTION NO. P226-8: Gateway CS1572FS the original problem was Q301(HV80) and IC301(UC3842A) was blown. Electrolytics in SMPS circuit checked O.K. Q303(MCR100-6) was replaced with ECG5405. There is a whine from the SMPS transformer as if it is not starting up.No power elsewhere in monitor. Checked R331(91k) O.K.  I checked the data sheet for the UC3842A and the Osc. looked around 20KHz. This is a common problem with these monitors. It is from the 180V supply being too high,

due to a feedback resistor going up in value, R331. Should be about 91K, unsolder one lead and measure it, if it's much higher than that, replace it. Then adjust the pot associated with it, VR303, so that the supply you measure across C321 is about 185V. Also Check R153, F301, Q301, ZD307, IC301, D307, A106, C116.  QUESTION NO. P29-8:  Dell D1528 Monitor That flashes the Green to Amber LED when powered up, however it justs keeps doing that and never powers up the screen Check for a shorted HOT. Something is shorting the B+. QUESTION NO. P36-6: Tengo un monitor IBM mod 6322 con el siguiente problema, no hay deflexion vertical esto ocurrio despues de averiarse el teclado e verificado el circuito de vertical y en una de las patas del tda 8351 hay 45v ¿es normal? ¿ideas?I have a monitor IBM mod 6322 with no vertical deflection due to damage to the keyboard. I checked the vertical circuit and in one of the legs of tda 8351 there is 45v. Is this normal? Ideas? If you have TDA8351, a 9-pin device, then pin # 6 can have up to 50-60 Volts in normal operation, and 45 Volts is a typical value. Pin 6 is the input for the supply to the flyback switch. If instead you have TDA8351A, a 13-pin device, this input is at pin # 8. For more information on TDA8351, download the datasheet from http://207.87.19.21/acrobat/2083.pdf.Si usted tiene TDA8351, un dispositivo de los 9-contactos, después un contacto # 6 pueden tener hasta 50-60 voltios en la operación normal, y 45 voltios son un valor típico. El contacto 6 es la entrada de información para la fuente al interruptor del tiempo de retorno. Si en lugar de otro usted tiene TDA8351A, un dispositivo del 13-contacto, esta entrada de información está en el contacto # 8. Para más información sobre TDA8351, descargue el datasheet de http://207.87.19.21/acrobat/2083.pdf. QUESTION NO. P36-3:  NEC XE15. When turned on, I get the orange (standby mode) power light. It does not change to green when video is applied. There is a high pitched squeal which increses in pitch and intensity as you increase the brightness controll. The horizontal output transitor tests as shorted when the flyback is connected but when it is disconnected it tests good. He suspects a bad flyback but is not sure.Suspect the damper diode[s], and any other components around the hot. Try a flyback tester [ringer] if available. The diodes within the flyback [tripler] also may be defective or shorted truns within the flyback. Check external components first before condemming the fbt. Look for any signs of perforation thru the casing of the flyback. QUESTION NO. P36-2:  Three Samsung cvp4237p monitors with the exact same snag, no picture, no hv at anode, and a very good purple glow in the crt neck. Disconecting the crt plug and hv comes up. I believe there is a short in the neck and want to confirm but I need a pin out of the crt for this model. Can someone provide a pinout?I bet you will find a crack in the neck under the yokes. Sounds like poor quality tubes or over-tightened yoke hardware may be to blame. QUESTION NO. P219-6:  Three IBM 9518-001 monitors with problems in the vertical, there is no stable image.The 95xx series monitors are XGA variety. Which translates to a special type needing a

different drive signal, otherthan a std vga signal. Symptoms are loss of vertical and horiz sync.  QUESTION NO. P220-2:  IBM 8512-001,with problems in the vertical, there is no stable image. Change the resistances of adjustment, no results.Verify that pin 14(Vert.Sig) from the cable end position to the chassis is not open. These IBM cables have been known to open very easily. Generaly kinks at the cabinet input area are common.Check the capacitor that is across the vertical yoke pins on the mainboard. SuperCom ST1496 Monitor looses horizontal and vertical sync after warmup of about 10-20 minutes.Replace Weltrend WT8052 (IC-U505) Left/Front of mother board.Using a coolant after unit goes out of sync will confirm this repair QUESTION NO. P219-2:  Burned components on power supply board in monitor AOC model:cm-335.  What is the value of ZD904?ZD904 is 6v/1watt. You can use ECG 5070A. QUESTION NO. P210-4:  Dell VI1428U made by Lite-On, many power supply caps were bad and replaced, Power and high voltage is present but still have no video and monitor is squealing. I have about 10 of these models.Check the values of R436 resistance and R437 is located near the fly-back. They should be 1M ohm.. QUESTION NO. P213-10:  Tatung CM14SBS monitor. The picture does not fill the 14 inch screen fully.  If strecthed to fill screen picture not symetrical. The picture looks good with 1/2 inch black border around it.Is this a design flaw with this monitor?  Tried adjusting B+ and internal horizontal width pot. You are correct this monitor was designed that way. You will have about a 1/2 inch border at both side. QUESTION NO. P25-1:  Packard Bell monitor Mod# 1402S. It originally had no vertical deflection. I replaced vertical IC TDA4866, and R612 1ohm, half-watt, which was burned. I hooked it up, and all was well, except for the tint. I disconnected the monitor from power and deguassed the crt face as I would a TV. Reinstalled it in the case. Hooked back up for a final check. Now I have no raster, and an arcing noise. I viewed the chassis with no ambient light, and could not see the arcing. I had 8KV on CRT anode lead before, and now I have zero. What have I done wrong? Check capacitor C812 47uf 160 volts. Also cut the nylon tie holding the high voltage lead going to the CRT circuit board and inspect the wire for breaks in the insulation. I also found three bad capacitors on the CRT board on the 1402s that I was working on. I do not remember the numbers, but they were the small caps about 1uf at 100 volts. Two of them were yellow in color. QUESTION NO. P127-1: Looking for help on NEC Model JC-1433VMA with no video symptom. Powers on but no video.

Key items were missing in your question. Does the HV cycle on and stay on? This is confirmed by either HV Voltage probe or by hearing the crackle. If HV is present is the filament lit? Either or both would cause no video to appear.  QUESTION NO. P25-5:  CTX monitor model #CPS1760 LR. Comes up with video very slow, checked for bad caps & fly-back; check OK. Is there a series of caps that go bad & where should I check?Replace electrolytic caps in secondary psu. They are next to the diodes in the secondary supply. QUESTION NO. P120-1: 14" monitor with EMC tube, and the brightness is very high (white screen). I am already checked the pot, and is ok. In the CRT board, I changed the LM1203 and there is no effect. I already checked for bad resistors, but they seem to be ok. I checked de capacitors and it seems to be ok. Is the problem in the CRT board?CHEQUEA LA ETAPA DE G-1 SI LA TENSION ES DEMASIADO ALTA TENDRAS PROBLEMAS DE EXCESO DE BRILLO ( -10V A -50) APROXIMADO ES CORRECTO. QUESTION NO. P22-3:  Supercom SK1592 monitor in the shop which suffers from excessive width and pincushion. Width and pincushion controls have barely noticable effect. I have yet to locate the defective part. Has anyone else dealt with this model and/or problem?Check the deflection yoke for shorts QUESTION NO. P24-3:  Several IBM 8515-001 monitors all of which have a hole in the lopt. After replacing the lopt and checking the hot the unit starts and then goes into protection immediately and switches off, even the led goes out. It is not a short on the secondary of the psu. I have tested.the new lopt works in a working unit. The vertical ic appears to be ok.Check for a bad capacitor to the rear of the board, near the lopt. QUESTION NO. P15-3: Mitsubishi monitor model# C-6922AGK the monitor works fine while in windows 95 (640X480) but if I shell out to DOS the monitor scrolls vertically as if the sync is missing.Using Device Manager, Remove, then re-install your video drivers. It sounds crazy but it worked for us! QUESTION NO. P114-3:  Tosh CF3048 which seems to have a pincushion type problem. The raster covers the screen but the video looks bowed in on the sides. Also there are slight vert retrace lines at the top which I think is a separate problem.Possible causes are corroded C305 (near vert IC) & C301 (near Center of main PCB). Both caps are Red & must be replaced w/ 2.2uF/50V - 105c high temp caps. QUESTION NO. P126-9: Orchestra French Horn 15" that has a pin-cushion problem. The sides of the picture in the display bow in. The pin-cushion adjustment pot inside will not adjust the problem. It seems to be something other than the pot. I have adjusted that pot in the past with results.

This monitor has probably FCC KD-1500 or KD-3500 made by KDS. If so, replace cap c636, 3.3uf/250v. Try to relocate it as far as possible from heat sink. It will solve your problem with pincusion.  QUESTION NO. P23-3:  IBM 9517-001 monitor with a sync problem. It will sync at 640 x 480, but will not sync at any other frequency. The display appears to be shifted to the left, and when entering Win95, display goes completely off, and appears to be at the top of the screen. In other responses on this service, similar questions were answered the monitor being an XGA and not capable of VGA and SVGA. Is this monitor an XGA as well? BM monitors with model numbers beginning with "95" are XGA monitors. These monitors are generally not compatible with VGA/SVGA systems. QUESTION NO. P122-7: Gateway CrystalScan 1776 LE monitor in for repair. Gateway has looked at this monitor, and has been unable to solve the problem. With the brightness at normal to high levels, there are several light bands that can been seen, going from top to bottom, at the left side of the screen, whose total width covers approximately 3 to 4 inches of the left side of the screen. I would check the cap that are filter for the video ic lm1203 or similar. I had some that had bad esr. If you do not have a esr cap meter jump a good one across it. Sometimes the cap check good on cap meter but esr is no good. I have also seen bad crt doing the same problem it look like a image being inserted on top of video. QUESTION NO. P129-8:  CTX monitor model# CPS1760 LR. It has a vertical collapse. I have changed the vertical IC7838 & checked for bad transistors. One common problem giving no vertical deflection in this unit is bad solder joints on the pincushion correction PC board, near the top of the yoke. Check carefully and resolder: often very hard to spot the bad joints. QUESTION NO. P15-4:  Multiple DX17F's which routinely fry the HOT. I have replaced all the normal parts HOT, C123, C120, L105, R177.D116, Q116. They all seem to work ok then but have squashed text on very right side.  Does anyone have the recommended proceedure for setting the current through the HOT?Check C134 and C908. QUESTION NO. P122-6:  Gateway 200 (Vivitron) 17" monitor that invariably goes into power save mode on startup. If I push the reset button I get the message 'out of scan range'. +12vdc drops to 1.6vdc."Out of scan range"indicates a disconnected data cable, more accurately no signal to the monitor. The power save feature powers down most of the unit if it doesn't detect a sync signal, assuming your pc is off, inactive, etc. Check cable continuity closely. Somehow unit the is losing signal. QUESTION NO. P119-10: Does anyone know how to open the case of a Apple MultipleScan 15 Display?There are two small holes at top of the monitor. Insert a small screwdrive into the holes and push tab down while pulling apart. 

QUESTION NO. P123-3:  Packard Bell 1402S monitor that has a burnt resistor that I cannot find the value for. The location is R454.I measured the value of resistor R454 in a Packard Bell model 1402s as 222.7K ohms. The color code looks like red, red, black, orange. The body of the resistor is green.  QUESTION NO. P120-7: I investigated a color purity problem and determined that portions of the office furniture were magnetized, especially near the seams. I assume spot welding does this. I used a fluxgate dc meter and found 1-3 gauss dc near the shelves and drawers. The user does not believe this is possible. Am I correct, is it possible that office furniture can be sufficiently magnetized to cause color purity problems, and are there any references on this phenomenon? If I am correct I intend to attempt to degauss the affected metal pieces of furniture.Absolutely !! I have a customer in Lake Orion, Michigan who has a steel beam in his residence magnetized. The house has been hit by lightning. There are only two physical places in the house he can have a colour tv with a half-way desent picture. The probality of the steel office furniture being magnatized is very possible. The companies who manufacture these items usually degauss them before shipping.  QUESTION NO. P120-6:  Sony CPD-1425 with a "no power" symptom. The start up cap at IC1 is not charging to 16v to start the PWM chip. I have changed the start-up cap C14 without the problem being resolved. I notice that when the main PCB is flexed some; C14 will charge to a slightly higher voltage and occasionally cause the PWM chip to start.I actually solved this problem; I over looked the obvious as we all tend to do from time to time. The problem was solved by replacing the DPDT Power switch. On one contact the resistance was around 600Ohms when closed, and the other close to zero Ohms as it should have been. Found replacement (exact replacement) through MCM Electronics. Dont let this one catch you! QUESTION NO. P115-1: Have a Sony KV-32XBR70 TV that has vertical jumping of the horiz. scan lines. May be aprox. 10 lines jumping or spreading apart at a random position and rate. Only seen thru out top half of picture. Also I notice a audible noise that seems to be in step with the random jumping of the scan lines. I suspect the noise may be coming from the yoke.Is the deflection yoke bad?No. Probable breakdown of one of the active devices in vertical deflection. May be cap breaking down, also check components in PCC circuit. QUESTION NO. P116-10: Goldstar GHV-1280M VCR. Need voltage regulator information, ie part number, replacement type, etc. The suspect IC is D101. The power supply works in European voltage, but not 110 vac. All voltages are low, and I believe the regulator cannot handle it.European Voltage? 220, 208, or what? That unit may be set for 220 input. Plugging into 110 will cause all voltages to read low and may cause some items to overheat. Findout what you are working on, get the proper matching transformer for the AC supply, then troubleshoot. QUESTION NO. P116-5:  Several NEC 2A monitors (JC 1403HMA) with similar symptoms. The display is out of focus when turned on. The picture focus improves the

longer the monitor is on. One of the monitors appears to have healed itself, meaning the focus and brightness are good at all times, however, when the computer is turned off the raster is visible (not blanked) and a few of the retrace lines are brighter than others. ANSWER 1: How old? Possible crt, suspect crt socket for high resistance path from focus to grnd. Other things may be failure in Focus supply from FBT or focus/screen control assembly. ANSWER 2: Sounds like it is temperature related, possibly a bad cap. Try using a hair dryer to heat up components and watch for inprovement. QUESTION NO. P116-3: Working from your advice, without a schematic, on a dead CTX-1561. Swapped out R114, R111, R112, R113, ZD101, ZD102, 2SK955, and 2SC3886A. Good picture for 90 seconds, then horizontal raster collapses and blows fuse. I need the values of D101 and D108.Possible flyback may be breaking down. Use a ring tester if you have one. Check yoke for possible worn coating on coils esp those in contact woth dag coating of crt. Does FBT become hot before fuse blows, does yoke become hot? Doubtless the Hout fries but overload somewhere in def sys is problem. May even be leaky cap in hz out ckt.  QUESTION NO. P116-1:  JVC 860 & 870 both with the same problem. When plugged in the relays click but the machine will not power up. On the 860 I have changed c6,q1,q2 and c9. On the 870 I changed just q1 and the bridge rectifier as it was blowing fuses at first. What is interesting is that if I press the top of c9 with my finger (it sounds as if its leaking) the machine will power up. I have changed this cap in both machines though and it made no difference at this point.Pressing physically may be flexing the pcb beneath the components or components may be mechanically damaged. Check with a good magnifier for cracked foils or pcb. Also check the solder connection for ring cracks or dirty connections, remove components, clean foils, and reinstall. Keep looking for the not too oblivious cure.  QUESTION NO. P113-4: I need the value of resistor 409 of DAEWOO monitor, model CMC-1501BA1.The value is 120 Ohm, 1/2 Watt. QUESTION NO. P113-8: IBM model 5154 VGA, no raster, no green power LED. Before total failure it was having trouble displaying the first couple of characters on left hand side of the raster.The switching PSU is a modular plug in. I've pulled the horz transistor, it checks OK and does not solve the problem. Have replaced the main IC in the PSU, a SG 3542 switch mode control IC, and this does not solve problem either. Input caps and rectifiers SEEM to perform OK and produce a good 300 v D.C. One clue is the supply to the IC which is usually shown as 28 v D.C. in the data sheet is made from what appears to be some sort of complex boot strap circuit whose source is the big output transformer. Am I chasing my tail on this one ? This sounds like a classic P.S. failure. Other P.S. that I've repaired had low valued caps in the current sensing curcit. I recall there were 3 electrolitics 10uf, 1uf. & 47uf(not sure). All were grouped together at the top of the board. I assume you have checked the MJE13005's for countinuty.  

QUESTION NO. P19-2: IBM - 8514 monitor Diag - dead, fuse is okay.Other symptoms would be helpful. As unsual noises squeals, humming. etc.Any LED indications. Two distinct problems come to mind. One is open/shorted HOT. The other is shorted low voltage cap on the video board, something like 100uf @50vdc. QUESTION NO. P1226-3:  Where can I get the pin out for the data cable of an Emerson monitor? I think that this cable is all that is wrong with the monitor. It has a mitsubishi crt in it. Other than that i have no info on it except that it is a 14" svga.  No model # is visible.Computer Component Sources in NY. They have a complete line of replacement cables. Voice 800-356-1227 Fax 800-926-2062 International 516-496-8780. QUESTION NO. P113-7:  Toshiba cf2010j with a vertical deflection and linearity problem. The bottom half of the screen is black and the top has some foldover. I have replaced the signal processing ic and the vertical output chip to no avail. I have also substituted a good yoke with no repair.Check any diodes and caps connected to the vertical def ckts. Also confirm correct voltages at vert out device pins. I suspect you will find a cap that has opened or one of the bias voltages is not right. QUESTION NO. P19-8: I am looking for the pin-out assignments for a Commodore 1902A monitor, particularly the 6 pin din socket for the composite video.Pin identies as follows looking at plug end.Pin 7 & 8 no connection Pin 6 Color out. (Chroma sig out)Pin 5 Audio in.Pin 4 Video out. (Composite Sig out)Pin 3 Audio out.Pin 2 GroundPin 1 Lum/Sync. ( Luminance/sync out) 8 73 6 1 Plug output from C645 4 back of unit.2  QUESTION NO. P1222-4: U.S. logic model MM-50,FCC#hsutrldh-1570,mode select problem.no schematic.traced h/v sync lines from input cable to an ic203(74hc14n).replaced,no help.traces also lead to ic401(tda9103)suspect this one.only mode ok is 640x480 and 640x350.all others only display the top third of display,with lines running thru, like a vertical distortion.Does freeze-spraying the TDA9103 affect the symptom? If so, refer to the answer for Question No. P1218-2 on monitor repair. QUESTION NO. P1218-5: Gateway 2000 DX17F monitor that keeps smoking R177 (1 ohm 2 watt) . I have replaced R177,Q116,C120,C123 and checked all my solder connections. R177 smokes with the data cable in and out.Besides the components you replaced, there are other problem components in these units. See http://www.monitor-repair.com/rd102.htm for further information.

Regarding this answer, The URL is no longer working. Can any one tell me a valid address for this information? QUESTION NO. P1211-2:  IBM model 9518-001 VGA monitor , on boot up the vertical sync is out and a loud squeal when windows starts the colors are blurred, as soon as program manager loads every thing is normal.IBM 9518 is a XGA monitor. It will not work with VGA or SVGA mode. QUESTION NO. P1211-8:  CTX CVP 5468NI, missing the resistor #303. Can anyone tell me the value?The resistor R303 is 270K Ohm Red Violet Yellow QUESTION NO. P129-1:  NEC / multisync (3DS) M# JC-1404. The video is fine except there are 2 vertical blue bars about 1 1/4" wide on the right side of the display separated by about1 inch. I replaced the 51387 IC with no difference. I also replaced the 3 1Uf 160 volt capacitors as they were reading low.Look at question/answer #P1210-8. The problem and solution are what you need. Replace all 3 caps 2.2uf @50vdc off the video processor. QUESTION NO. P121-10: Princeton multi scan monitor M# eo15 FCC# evokd-1510 Factory # gs 04 Unit has no picture, have tried adjusting brightness to no avail. Has high voltage.Closely inspect the video board on the tube socket. Look for break in the 12v line to the video chip. These are notorious for breaking. Also look for cold solder joints on the tube socket.  QUESTION NO. P1218-8: Gateway cs 1776le(17",front panel backlit lcd display model,fcc#iawmx17f) shorted yoke drive HOT 2sc4924.replaced with generac part,3.9 ohm 2 watt feeding b+ to it open,replaced.Now a pincusion preblem,can't adjust with rear p.cush.control pot. this pin cush. problem was not there before failure.is the HOT type critical? what other parts are likely? Did I "inject"the new problem? Since pincushion is a function of the yoke circuitry, where do I go now?I located two shorted transistors,"Q909" and "Q506", both 2sd799, darlington power transistors, one on heat sink, and the other stand-alone. QUESTION NO. P1121-6:  Princeton Grapic 15" Multi sync E015 The display is very dim.Check the filament/heater voltage, it should be around 6.3 volt. If it is too low, check the power supply capacitor. QUESTION NO. P121-4: I have never manage to repair a monitor which has a smearing problem.I have seen monitors of various brands with a smearing problem either on the right side or on both sides.  Several times I have changed the electrolytics on the video board without any success.The smear on the right side usually is a bad tube problem. Sometimes it can be fixed by reactivating the tube, but you must have the tool, check Sencore's home page. QUESTION NO. P1218-2:  Two Polarius monitors (model# 4AL-N).Both are new and the

company that sold them no longer exists.They go out of sync after running continuously for 30hrs.They will run forever with cover off. By heating and cooling sync processor (TDA9103) I can simulate the problem.A number of these ics (TDA9103) made by SG Thomson proved to be defective. Change the ic and in order to completely solve the problem cut a piece of copper shield a little bigger than the ic and glue it on the IC.Then solder this shield to a ground point or pin 19 of the ic.  QUESTION NO. P1218-4:  KDS-1700V (Korea Data Systems) Monitors that appear to "blow up" for no reason. The problem is Q414 goes short for no apparent reason. This damages Q416 and T401. This can also blow up the power supply. This appears to be a design problem. Can anyone recommend a fix ???. By replacing the above parts (and repairing the power supply) this can last for between 1-2 days and 6-8 weeks. I currently have 40+ monitors with the same problem.Re-Work Procedure For: KD1700v,Orchestra Tuba2, Princeton Graphics Ultra17 Plus 1. Unpack monitor box, remove packing foam, and plastic bag.2. Remove back cover and base.3. Remove top and metal cover.4. Remove bottom metal chassis and main board metal frame.5. Pull out main board and disassemble main board from all the metal frames.6. Change T401 (H. Drive Transformer) P/N KDS2036 to a KDS2036A.7. Remove the black substrate HIC401,R444,Q413,R460 and BC401.8. Change HIC402-PT1 to a PT1A. (use adapter board).9. Add resistors C.F.R. 100K ohm* W on PCB pattern-side of R920.10. Install 3 jumpers size 2 each 6.5" and 1 each 8.5".11. Pin #2 of expansion board to R420/J464.12. Pin #7 of expansion board to Q416/BC401.13. Q413/collector (on mainboard) to T403/R416.14. Replace R460 from 51 ohms 1/4w to 32 ohms 1/4w on pcb.15. Mount the new expansion board in location HIC401. Make sure pin #1 is to Pin #1 (have option board component side facing component side.16. Install R920 100K ohms 1/4w in parallel on the solder side.17. Fix each jumper by jam-melt,so they do not move. (Make sure each jumper wire is clear of screws when it is installed)18. Adjust VR901 to 26kv using a high voltage probe.19. Adjust brightness and focus.20. Re-Assemble monitor and mark with a blue dot on the product label near the serial number.TIP: No video Solution: Check to see if ZD402 is installed, if not then add add a 1K ohm resister in it's place. TIP: Video Jitter Solution: Add a ferrite bead at J402 (use the same one removed from location BC401. PS: Make sure the screws do not penetrate the jumper wire (pin #7) when attaching the back plate on thr pcb. One of the problems with these monitors is that some svga video cards, when they change modes, put out a very fast rise time spike on the horzontal line and it kills the horizontal

output transistor MJM16212. This can be stopped by opening the horizontal sync lead from the monitors video input db-15 connector and inserting a 3/8 ferrite bead in series with this line. This should stop this very fast rise time spike from destroying the horizontal output transistor. QUESTION NO. P1217-9:  Three Packard bell monitors model 2020. They come up run for a few hours then just shut down. The led on the front changes from green to yellow. just turning off the monitor and right back on it comes up runs for a few hours.There is a common problem with 2020's (same as PB 1512SL): arcing from the CRT takes out any or all of 3 nearby IC's: IC701, IC702, IC703. The most likely culprit with these symptoms is the IC703 EEprom, usually a 93C56 or 93LC56, especially if holding down the 'Select' button replaces the on/off symptom with an out-of-sync condition, but more than one chip can be zapped. Program a new EEprom from a known good chip, or get a preprogrammed IC from an outfit like LJ Enterprises (800-627-8755). Note: the problem can recur, unless the chips are shielded from further arcing damage using a strip of metal connected to ground. QUESTION NO. P1117-4: We have many Gateway 2000 model CrystalScan 1024Ni. The problem is that the image jumps horizontally, and the picture is unstable. Only when the horizontal size control is set to expand the image at minimun, the image turns stable.>From another tech: I got a couple of these monitors in for repair also never found the problem but I definitly know that the problem is not on the main board as I changed it with a good working one.The jumping horizontally on the gateway 1024ni turned out to be an intermittant front panel control. Disconnect horizontal cener potentiometer and substitute a similar one as test. QUESTION NO. P1210-8:  NEC Multi sync 3DS M#JC1404HMA-2 14" monitor. On the right side of the monitor are 2 blue bars about 1 1/4 inch wide running vertically with a spacing of about 3/4 inch. I replaced the 1 Ufd caps on the video board and the M51387 IC with no change.Check the 3 2.2uf 50v ccaps below your 51387 color processor.  QUESTION NO. P122-2: Several times I have tried to repair monitors which would change display sizecontinously (increasing and decreasing size in all directions at about 2mm).All the voltages at SMPS output seem to be ripple free. B+ is ripple free too.Also nothing seems to be peculiar at CRT pins, either G1 or G2 or color cathodes.Any ideas?The problem you are describing sounds like high voltage regulation problems. The easiest way to tell is by changing from a black raster to a white raster. If the size changes quite noticeably or jumps alot then you have a regulation problem. The first thing to do is check your high voltage while changing the raster from black to white. If the HV varies by a large margin, then you have a flyback problem. If it doesn't, check the voltage at the collector of the HOT while varying the raster again. If the voltage changes alot then check your B+ line. Typically what goes out in this case is a capacitor(typically 100uf-350v or so) or the B+ regulator. Hope this helps. QUESTION NO. P1210-9: We have three Apple monitors, "Color Plus 14" Display", model number M1787, FCC ID: BEJCA453 and made by Goldstar. The common problem

is that the display is too wide. There is no external adjustment and the internal H-SIZE pot. has next to no effect.   One curious correlation is that of the seven of this model that we have, these three are also the only ones without screen savers running.ANSWER 1: I do not know the specific model but most probably its a faulty transistor.If you check the H-size pot you will see that two legs are connected to ground .Follow the third leg and will lead you to a transistor .This is the most probable fault.ANSWER 2: Check for a 10uf 160v near the flyback this will cause it to be too wide.ANSWER 3: Try C721, 47uF @ 100V. It's just to the front of the flyback xformer shield/heat-sink. I think the component is under-engineered: it's pretty small for those values. QUESTION NO. P123-2:  Digital SVGA monitor, model# PC7XV-DE. I am unable to get the colors adjusted correctly. The only way I can get white is if I turn up the green drive all the way, and turn down the red and blue drives all the way. I tested the crt on a Sencore CRT Analyzer, and it tested ok. I am unable to locate the bad component.Check all electrolytic capacitors on the crt board w/capacitor tester. Scrape glue from component side of crt board (it becomes conductive as it darkens with age). Check for open or increased value resistor in green circuit. Resolder video output transistors. QUESTION NO. P128-3:  Samsung 14" monitor CPV4237P The problem is that the video is real faint and can only be seen if it is dark in the room. The HOT seems to be ok and the secondary supply voltages are 151V, 93V, 23.9V, 7.2V, and 6.1V to the heaters. The voltages on the 2 test points near the flyback are 150V, and 86V B+FBT, are these correct or do I have a bad CRT?The problem you are describing is definitely a bad picture tube. Very common with these models. QUESTION NO. P1121-9:  Two Peri Max SVGA units with same problem. Dim video, brightness and contrast controls do have an effect but at max still dim. I replaced the LM1203N and some high esr caps on neck board no effect.If you've replaced LM1203N, try going to the National Semiconductor Homepage at www.national.com there you can download the datasheet for the LM1203N video amp. There is a schematic of a "typical application". Sounds like you have a problem in one of the clamp circuits that control brightness, etc. >From the datasheet you should be able tofigure this out.I have seen a few of these with this symptom. Try shorting pins 12 and 13 on the LM1203n this will be full contrast. If the screen does not brighten up to normal you probably have a bad CRT. I have replaced a few.  QUESTION NO. P1126-1: Gateway Monitor CS1572fs - Screen is wavy -clear but wavy - and unit whines.B+ is high. Check for open resistor R329 91K 1W. Adjust VR303 for 180V.  QUESTION NO. P123-3:  Burned components on power supply board in monitor AOC model:cm-335. I need the value of resistors R937, R927, R941 & diodes D942 , ZD951?R937=820ohms, R927=1Kohm, R941=270ohm, D942=ECG915, ZD951=6volt. 

QUESTION NO. P122-8: Could someone please tell me the value of R105 in a CTX 1451C monitor?R105 is a 91K @5% 1/8w. QUESTION NO. P1112-7:  CTX CPS1760 LR has lost it's horizontal size adjustment. The screen is barrelled at the sides (squeezed in the center). All three other screen adjustments work fine.Look for blown components in pincushion correction circuits. May be active or passive devices. Suspect electrolytic capacitoI have this same monitor that had the same problem. Check vertical deflection amp (it's on the very bottom board near under the plastic plate, tward the left side, I belive). After I replaced this, it worked fine. 

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Monitor Acer 7011Web Reparaciones de Paco Alvarez

      Averias típicas      Modelo Acer Monitor 711

      MONITOR ACER.      MODELO 711 D.

      FALLO "EN CADENA", DE CIERTOS COMPONENTES DE LA FUENTE DE ALIMENTACIÓN.      En este caso, los siguientes componentes estaban defectuosos:--      El integrado de control, IC601 / UC3842 ("reventado").      El transistor de conmutación, Q601 / 2SK793 MOSFET (cruzado).      Los cuatro diodos del puente rectificador de la red -- D601, D602, D603,       D604 (cruzados).      Además, estaba quemada; la pista entre R616 / 1K, 0,125W y el terminal de       la "Vigilancia de la Corriente", CURRENT SENSING; de IC601.

      SIN SINCRONISMO HORIZONTAL. EL MANDO DE USUARIO DE CENTRADO HORIZONTAL NO       FUNCIONA.      Después de mucho buscar la causa, se decidió ir comprobando los       condensadores asociados a IC251, TDA4852, y la avería se arregló al quitar       C268 (220 pF), que se sustituyó por uno nuevo.

      INTERMITENTEMENTE, PIERDE LA DEFLEXIÓN VERTICAL (SE RECUPERA GOLPEANDO EL       APARATO)      Soldadura defectuosa (apenas visible) al conector del yugo.

      NOTA IMPORTANTE: El autor y webmaster de este sitio web autoriza el uso de       esta información solo para uso particular. No se pueden publicar en grupos       de noticias ni en otras páginas web. Contactar con webmaster para       cualquier aclaración CORREO

      Web Reparaciones de Paco Alvarez

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Monitor Aoc 4S (similar al 4N)Web de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      4S (similar al 4N)

      MONITOR VGA      MARCA AOC      MODELO 4S (SIMILAR AL 4N)

      ESTE MONITOR NECESITA ENTRADA DE SEÑAL PRESENTE PARA ARRANCAR.

      NO HAY IMAGEN. LED VERDE PARPADEANTE.      Transistor de líneas cruzado entre base/emisor y colector. (Q405, 2SC4769)       Se sustituye por un S2055AF, que, igual que el 2SC4769, mide resistencia 0       entre base y emisor sin que esté cruzado entre base y emisor. Al cambiar       el transistor de líneas, conviene verificar el condensador conectado a su       colector, los otros condensadores grandes de los circuitos asociados,       verificar las soldaduras de la zona, especialmente de la bobina L403, que       suele estar deteriorada; si así es, comprobar la resistencia conectada en       paralelo con ella, R427 (1 ohm., de seguridad); cuando esta resistencia se       quema, aparecen unas franjas verticales oscuras en el borde izquierdo de       la imagen, y el transistor de líneas se calienta excesivamente.

      PANTALLA BLANCA MUY BRILLANTE, CON LÍNEAS DE RETORNO VISIBLES.      La imagen aparece bajando un poco el control SCREEN del transformador de       líneas, pero el control de brillo no opera.      R716, 220 K, cortada. Conectada a uno de los terminales del potenciómetro

      de brillo.

      FALTA EL COLOR VERDE.      En el amplificador del verde de la placa del zócalo del TRC estaban mal:      Q814, 2SD756      R856, 4'7 ohm      R855, 1'2 K      

      (C) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Monitor Aoc 4VIRWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      4VIR

      AOC MONITOR

      MODELO 4VIR

      NO HAY DEFLEXIÓN VERTICAL -- SI ES PRECISO, VERIFICAR LA EXPLORACIÓN       VERTICAL, ELEVANDO LA TENSIÓN DEL ÁNODO ACELERADOR (G2) DEL TRC.      El integrado de la etapa vertical es del tipo TDA8172. Si este integrado,       su circuito periférico y su tensión de alimentación están bien; es posible       que la avería esté relacionada con el integrado que contiene el oscilador       vertical -- o sea, el * TDA9102C.      La señal del sincronismo vertical entra en el terminal 14 del TDA9102C y       la señal de la rampa del oscilador vertical está presente en el terminal       13 del integrado. Y la señal que excita el TDA8172, sale del terminal 15       del TDA9102C.      Si la señal de la rampa del oscilador vertical está bien (terminal 13)

      pero no hay señal de excitación vertical (terminal 15) es probable que el       propio TDA9102C esté defectuoso.

      * MUY IMPORTANTE: es imprescindible reemplazar el TDA9102C con un       integrado exactamente igual. Los tipos del TDA9102 cuya letra de sufijo       que no sea C, no funcionan en este monitor.      

      (C) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Monitor Aoc 4VLRWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      4VLR

      MODELO 4VLR

      IMAGEN BAILANDO, INESTABLE.      El condensador de filtro principal, C907, estaba reventado: 150 mfd. 400       v. Los demás componentes de la fuente bien.

      MUERTO. SE OYE UN "TIC TIC" MUY DÉBIL.      El transistor de líneas, Q408, estaba cruzado (2SC4769, equivalente       BU508DF o S2055AF), y el terminal central del transformador de líneas con       soldadura deteriorada.      

      (C) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Monitor Aoc CM313Web de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      CM313

      MONITOR MARCA AOC.      MODELO CM 313.

      REPETIDOS FALLOS DEL TRANSISTOR DE CONMUTACIÓN, DE LA FUENTE DE       ALIMENTACIÓN, Q901.      Este monitor funcionaba las 24 horas del día, en un ambiente de mucho       calor.      En el caso del fallo reiterado de Q901, conviene comprobar la resistencia       &#8220;Vigilante de la Corriente&#8221;, CURRENT SENSOR, R925 / 047.      Además, es posible que haya una problema con el circuito que &#8220;Limita la       Corriente Máxima&#8221;, CURRENT LIMITER. Dicho circuito consta de R926, R928 y       el transistor Q909.      Se trasladó el monitor a un lugar de menos calor, y -- desde entonces --       Q901 no ha vuelto a fallar.      

      (c) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Monitor Aoc CM335Web de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      CM335

      MONITOR AOC      MODELO CM-335

      SIN DEFLEXIÓN VERTICAL (LÍNEA HORIZONTAL CENTRAL)      Diodo D202 abierto (1N4001). Es el que proporciona la tensión de 21 v. al       terminal 2 (entrada de alimentación de la etapa de potencia) del integrado       de vertical IC202 (TDA1675). Se cambia por un 1N4007.

      NO FUNCIONA NADA.      Fusible F101 (2 A.)quemado; al cambiarlo vuelve a quemarse. Hay       cortocircuito en terminales de entrada de alterna del rectificador BD10,       pero al desoldarlo y retirarlo de la placa se ve que el corto no está en       el rectificador y sigue estando en los puntos de soldadura. Después de       comprobar los componentes desde el interruptor hasta los mencionados       puntos, finalmente se soluciona la avería sustituyendo la resistencia PTC       del circuito de desmagnetización(PTC101), que a simple vista no parecía       estar mal.      

      (c) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Monitor Aoc CM335-MGWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      CM335-MG

      MONITOR AOC      MOD. CM335-MG

      De este modelo (similar al MG335) hay por lo menos dos versiones, una con

      la fuente de alimentación en placa separada, montada verticalmente al lado       izquierdo (posterior), y otra con la fuente en la misma placa base.

      MODELO CON FUENTE EN PLACA SEPARADA      "MUERTO".      -Fusible quemado (2,5 A.), y uno o más de los diodos rectificadores de red       en corto.      -Fusible quemado y transistor chopper de la fuente de alimentación cruzado       (TIPL763A; tiene muchos equivalentes, entre ellos el BUW13A).

      MODELO CON FUENTE EN PLACA BASE      HIPO DE LA FUENTE DE ALIMENTACIÓN.      Se debe al transistor de líneas cruzado (2SC4769, equivalente BU508DF). El       transistor nuevo no tarda ni 5 m. en cruzarse, ya que se calienta       demasiado. Examinando los circuitos relacionados, se halla C417 (47 mfd.)       seco, pero nada más, y el cambiarlo tampoco soluciona el problema. Según       el manual de servicio, parece ser que la destrucción del transistor de       líneas implica que el transformador de líneas es defectuoso, por lo que       conviene cambiarlo si se encuentra repuesto. También puede probarse poner       un transistor de líneas más potente, como un 2SC3997.      

      (c) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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Monitor Aoc CM336Web de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

      Monitor AOC      CM336

      MONITOR AOC.      MODELO: CM336.

      LA IMAGEN "SE CIERRA" HORIZONTALMENTE O/Y SE DESPLAZA LATERALMENTE --

      PUEDE SER AVERÍA INTERMITENTE, O PROVOCADA POR EL CALENTAMIENTO DEL       MONITOR.      Al calentar y enfriar alternadamente, el condensador C945 / 220mFd, 160VCC       y el transistor Q852 / 57419-Q, se observó un cambio de la frecuencia del       oscilador horizontal (usando el osciloscopio como instrumento de medida).      Al renovar Q852, C945 y -- por si acaso -- el zener ZD151 / 8V2, y       retocar el ajuste del potenciómetro de "Fase", PHASE de 31KHz y del       potenciómetro de F/V ¿frecuencia vertical?, la avería quedó resuelta.

      Según el manual de este monitor, el zener ZD151 no existe. Probablemente       se trata de un error del texto original, en inglés. El zener interesado es       ZD851, que está en el circuito del emisor del transistor Q852. Q852 es el       componente activo del estabilizador de la tensión de la línea de +16V (en       el circuito principal del aparato) y C945 es el electrolítico que filtra       la tensión de alimentación cuyo punto de origen es el terminal 11 del       transformador de conmutación, T904, en la fuente de alimentación.      

      (c) Paco AlvarezWeb de Reparaciones Electrónicas      de Tv - Video- Sonido... y más.

 

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