Archive Computer Monitor Repair

QUESTION NO. P51402-7: NEC Multisync C500 monitor (JC-15W1VMA). No control over horizontal width or pincushion/barrel from onscreen menu even though the menu appears to function correctly. Screen picture OK but only 1/3 in width.

Check for shorted base emitter Npn transistor in horizontal drive stage. Also review answer for Question P5002-10 Packard Bell A720 monitor which will explain how these systems work.

QUESTION NO. P53102-5: Dell 828FI monitor 800F series works fine until turned off and back on, or reboot PC, than LED flash green twice as fast (blinks when connected to non working PC and constant ON when computer is on) but no video. Turn monitor off and disconnect from computer for about 5 minutes, connect again, turn on and everything works fine again until you reboot PC or turn power off and on. When power cycled on off on I can hear slight buzzing noise (very slight) like it is not enough power to kick in high voltage ether on power supply or on the flyback. I replaced hot Q406 transistor and the D403 with no effect, replaced C503, C606, C515 nothing changes. Replaced TDA 9109, it did not help.

The micom ic202 supplies OSD,to the video board.vert/horz sync to TDA 9109. According to Samsung, check H/V pulses Pins 4 & 10 of ic105 NO check ic105 OK same H/V Pins 20&21 ic202 NO ic202.The other ic is the E2EPROM ic205..There is a reliability mod for this chassis. With chassis removed, clean the lower edge of the bell CRT. Glue a piece of foil (3inches wide 10 long) along the bell over-lapping the rim band. This is to prevent static discharge from the CRT from damaging ic302 or the CPU. Many of the common faults on this product are attributable to ic302.

QUESTION NO. P52902-5: I need value for R935 in Daewoo Monitor 710B.

R935 is 82K ohms.

QUESTION NO. P52802-9: ADI ProVista CM700 monitor is dead. Customer reported smoke then died. HOT appears ok. Need values of R970, ZD 902 and ZD903. All burnt beyond recognition.

In the schematic for the ADI CM700, R970 is a 47 ohm, 1/2 Watt resistor, and ZD902 and ZD903 are both 36 Volt Zeners.

QUESTION NO. P52802-3: Tiny 17N (CA-65) monitor, the PS 'clicks' (about 4 or 5 times a second) for five or six seconds then trips (led blinks) and then repeats this continuously. PS voltages are present but some low, Q719 seems to get very Hot.

Check/replace L705, C735, D704, D705, D707, Q706, and the flyback transformer. You may also need to replace that Q719, if the overheating has damaged this FET.

QUESTION NO. P52802-6: AcerView 54e has no green color (red & blue are normal) upon powering up. The green color appears flickering after about ten minutes or so, then the colors gradually/suddenly becomes normal and stays normal until turning off.

Resolder the CRT PCB, especially check connector P101 and the CRT socket. If this is no help, see if there is an intermittent in the video data cable.

QUESTION NO. P52802-1: Sony GDM20e21 monitor has horizontal retrace lines on a white background with no video at all. I checked all solder connections.

I believe you are describing vertical retrace lines, these are not normally seen due to the electron beam being blanked out during retrace period. Video signals on monitors are directly applied to the cathode via the CRT board and a driver transistor, from the video board in the computer. A quick check with an oscilloscope at the base of the driver transistor will confirm the presence of the video signal. A condition that will produce the symptoms you have described, is when the screen volts have gone high. Most modern flyback transformers have a screen volts adj as well as a focus adj. Try turning down the screen volts to a suitable level to see if it has an effect on reducing the retrace lines and restores the video. If this has some effect check also that the B+ line has not gone high. Any increase in B+ will also proportionally increase the EHT. Small electrolytic capacitors in the power supply are the common fault for over voltage situation, so if the B+ is high check them all.

First check/replace IC420 = CXA1907S, the usual culprit. If not IC420, then check IC405.

QUESTION NO. P52002-10: Packard Bell A720 monitor horizontal deflection decreases with increase in resolution settings. Unable to adjust out with user settings. Display only covers approx 80% on lowest res and aprox 40% on 800x600. Vertical deflection also increases at same time and is set to minimum. Tried to test HOT but inconclusive.

A general rule of thumb I use for solving this common problem with monitors: From the front panel controls for H width adjustments pulsewidth modulation is used, by varying the pulse width the resutant output is a variable DC voltage. This DC voltage can be followed through to the emmitter of a transistor in the H/drive stages. A variable DC voltage at this point will vary the gain of the Horizontal waveform. So look for a shorted base emmitter in this area of the circuit. The Horizontal transistor is OK, if it wasn't then the set would not work.

QUESTION NO. P52302-3: I need a cross for a H6NA80FI manufactured by ST, it is a Power Mosfet that is used in the switching power supply of a Apple multiscan 15 AV Computer monitor.

STH6NA80FI is an ST Micro N-channel Mosfet, in an Isowatt218 case, rated for 800 Volts, 60 Watts, Rds < 2.2 ohms. Nationwide (www.neiparts.com) is listing the original STH6NA80FI, on-line. If a TO247 insulator is used, then STW7NB80, listed by Mouser (www.mouser.com), could substitute. Or, IRFPE40 or NTE/ECG 2377, with insulators, might be tried, though these have higher capacitance values.

QUESTION NO. P52202-1: NCD nc782aa monitor FCC A3KM053 when powered up, just the green light comes on. Checked the hot, it was good but monitor is not getting voltage to the hot.

From the FCC# for that chassis, try checking the value of R3570 (1 ohm), located by the yoke connector on the main pcb. If R3570 is good, check the FBT.

QUESTION NO. P52202-2: Gateway with Sony CPD15F1 Chassis was completely dead. Replaced shorted HOT Q507 and SW REG Q503. Unit now powers up, but both green and yellow lights flash after a few seconds with no raster.

Try checking Schottky D508, and check the boards carefully for bad solder joints, and for cracked PCB traces & rivet grounds near heatsinks, transformers, etc.

QUESTION NO. P52202-3: Gateway 2000 CrystalScan 1776 LE Monitor when powered up there is a clicking noise coming from the main control board and power supply board. I discovered L105 transformer was discolored and very hot to the touch, I need the value.

L105 (Mag# T*l-281-103-UO) has an inductance of 4.5 mH, and it should ring good. Since yours is discolored, it is probably bad. For replacement, try Mag Innovision, or suppliers like Nationwide (www.neiparts.com), or LJ Components (www.ljecc.com).

QUESTION NO. P52102-7: LG StudioWorks 775N monitor. Clicking relay with a blinking green LED. Replace IC901 but is still the same.

Check Q706, Q719, and D704 for leakiness or short. If not, try replacing the three voltage regulator IC's, IC923 = 5V, IC925 = 12V, and IC304 = 8V, which may fail under load. If no help, then replace the flyback, LG# 6174Z-1012B.

QUESTION NO. P51602-5: Sony GDM-400PS monitor, red gun quits after about 30 seconds; retrace lines show loss of red too. No other symptoms, cable tests good. Not sure if chroma, driver, CRT.

Try checking at IC407 = FA4111 (Sony part# 8-749-013-74). The red signal should input at pin# 1, at about 4 Vp-p, and output at pin# 3, at about 50 Vp-p, to the CRT.

QUESTION NO. P51602-6: Tiny 17N monitor FCC BEJCB775B. The supply trips with or without a dummy load when active, but remains rock steady at 160V in standby. 11V rail as marked on the board down to 8V, but I reckoned that would come up when the supply sync to line after start-up. The line stages look ok on first pass, no shorts on ht rail that are obvious either. I really need a chassis ID.

That FCC number, BEJCB775B, gives your chassis ID. This FCC is for LG (Goldstar), and is also used for the LG Studioworks 775N, LG chassis family CA-65. In that chassis, start by checking/replacing the Voltage regulator IC's IC925 (12V) and IC923 (5V), and then checking/replacing the flyback (6174Z-1012 or similar).

QUESTION NO. P51602-7: Radius Intelicolor 0461 monitor starts the HV for 3 seconds then shuts down while the power and stand by leds are flashing. The 144 Vdc in Power supply from 145 V falls to 56 Vdc. The adjust led stays in SIZE.

This Radius is a Sony GDM-20E01 chassis. In that chassis, when the power & power-saving LED's flash, and the SIZE LED is on solid, this is an error code for a problem with the ABL (beam current) circuit.

QUESTION NO. P51602-9: Hewlett Packard Ultra VGA 1280 monitor, there is no label on the rear, so can't identify further. Pcb is labeled #code no BH41-10308N. Other markings on the pcb are # CMG73*7 MAIN PWBMP-6.3. The problem is that there is fold over e-w on the horizontal scan, both left and right symmetrical about 1" either side. R427 is burnt beyond recognition. The picture is good except at the edges where folded over occurs, there, it is de-focused slightly. There are no obvious short/open caps or diodes around this area.

The chassis code CMG73*7 indicates that this HP is a Samsung chassis, similar to the Samsung Syncmaster 17GLi (CMG7377). In that chassis, the value of R427 is 1K ohms, 1 Watt.

QUESTION NO. P51502-6: Compaq Monitor P75 model 625, would not start up. Replaced open R622,1.2ohms and shorted D615 (with a high current diode). Monitor starts up and operates of input signal from base unit, D615 gets warm, limited brightness control. What is the value of D615? What could be causing D615 to warm up?

This Compaq sounds like a Sony chassis. Is there a Sony FCC# or a Sony "SCC" chassis code on it anywhere, like on the label or on the CRT housing? If yes, it sounds similar to a Sony CPD-200GS, SCC-L07 chassis. If it's like the CPD-200GS, R622 is 0.12 ohm, not 1.2 ohm. D615 is a 200 Volt, 4 Amp, 30 nsec ultrafast diode. If you did not use an ultrafast diode, this could explain your diode heating up. Possible substitutes for this diode include MUR420, UG4D, BYV28-200, NTE576 or NTE619. Also, D615 could overheat if the filter cap beyond D615 were bad; in the CPD-200GS, this cap would be C632. Other components on the supply going to the CRT filaments for CPD-200GS, are pass transistor Q605, and R637 (2.2 ohm, 1 Watt); the analogous components in this Compaq could also be checked.

QUESTION NO. P51402-10: Philips C2082DAS monitor. I need the value of C839.

If this Philips is FCC# GZM1323, I show C839 as 470 pF/2KV.

QUESTION NO. P51402-8: Nokia multigraph 445M092 monitor. T41 (2SJ307), D30 (UF5404) and R172 (0.47ohms) are burned. I measured D31, D32, D39, the 12V SMD-Zener-Diode (Y2) on the backside between source and gate from T41. They should be OK. I changed the burned T41, D30, R172 but they burned down again after 5-6 hours.

Check inductor M3 for burnt or shorted windings.

QUESTION NO. P50702-6: Dell D1025tm monitor (Sony CPD200gs) has a fuzzy picture. The keys on the front are locked up. When I press anything but the menu, I get a picture of a key in the lower left corner. The menu will only let me move between two of nine menu choices. How can I unlock it? Do I need the DAS software to do it? Dell could not find anything about it and the Sony manual does not say anything about locking the menu.

The Sony CPD-200GS does have a "Lock" Option in its OSD Menu; perhaps the same procedure is used in your Dell. Press the "Menu" key, use the arrow keys to toggle Up/Down and Left/Right, to select the "Option" Menu (at lower right), and then press "Menu" again. Several Options will appear, including a Key Icon. Toggle up/down to the Key Icon, then use the Left/Right keys to turn it off. Regarding the fuzziness, try going to the "Screen" Menu (upper right), and adjusting the H or V convergence, or the Moire.

QUESTION NO. P50902-4: Apple Studio Display 17 [M6496]. A standard fault in this monitor seems to be that something arches (assumingly within the flyback) that can go on for a while until it blows up other parts and the monitor stops working. I've got a bundle of these monitors that have stopped working. What other parts (apart from the flyback) should be replaced? When repaired by Apple their list of replaced parts show a diode, a rectifier diode RL2, an 18 Volts zener diode of type MTZJ18, a 2K resistor, the 2SJ306 MOSFET and the flyback (6174T-13003C or 6174Z-1024B or Y2653820). The 2K resistor is easy to find as there's only one on the print (R555), the flyback and the MOSFET are also obvious but where are the other parts (what are their part numbers)?

Besides the flyback, check FET's Q503 = 2SJ306 and Q507 = 2SK2847. D502 is an 18V zener such as you have described, used for gate protection on Q503, but also check D505, the diode off the gate of Q507. The D503, off the drain of Q503, is either RL2 or RL2A (Sanken ultrafast types); double check your exact type, as RL2A is rated at 600V, 1.1 Amps, but RL2 is only rated for 350V. Also check IC501, Q203, Q204, R547 (47 ohm), and the small diode connecting to R555, which is D532 (similar in specs to 1N4448).

QUESTION NO. P50702-7: Viewsonic 21PS monitor, FCC GSS933006 does not show any red color on the screen.

A common failure for loss of a color in this chassis is a defective IC1302.

QUESTION NO. P50302-6: CTX 1769se monitor. I need the value of Q313, A TO 220 package has marking as top DD 54 bottom RC 7L4.

The TO220 device, DD54RC, will be a Sanyo Damper diode, rated 1500 Volts, 5 Amps, Trr under 1.5 usec. But I would re-check whether this device was actually assigned as Q313 (typically a HOT transistor), or whether it has a "D" prefix location assignment.

QUESTION NO. P50802-4: Sony cpd-200es monitor has no green color, red and blue appear normal.

Replaced Q512, irfli530, problem still existed. Final solution was a bad video cable, pin 2 was intermittent unless cable was flexed 90deg to connector, cable was replaced and the problem was solved.

QUESTION NO. P50902-2: Acer 7277c monitor. I need to ID R330, R329, R365, & Q322.

R329 = 240K, R330 = 80.6K 1%, R356 = 10K, Q322 = A673. Check Flyback, normally when R356 burns the flyback is bad!

QUESTION NO. P40302-6: Acer 7277e monitor, no FCC came in with FR707 burnt, replaced with a 1ohm resistor. Picture shows 3/8 inch wide black line running from top to bottom, about 1/3 of the way across the screen from the left side. Q312, Q318 running so hot you can't touch the large heatsink they are attached to without burning yourself. It only takes a minute to get this hot. I replaced C335 (220pf, 2KV) with a 330pf, 2KV (all I had to try). Now after on for a minute, picture stabilizes to a normal picture, but Q312 and Q318 are still VERY hot. Before changing cap, picture never stabilized. Checked all diodes, and transistors in the area of the pincushion circuit. Also all the electrolytic caps near there. All power supply voltages appear normal, (used a schematic of 7276e which is somewhat the same).

Fr707 is on the 45v line from the power supply area and this feeds q312 via L301. This would be the first thing to check for burnt windings it should be 2mh. Q312 goes on to feed q318 via q317 and from there to D305 via L302 the next thing to check it should be 150uh. You might also check D318, and Q302.

QUESTION NO. P41002-10: Acer 1554 monitor, how do I set the color balancing? These monitors do not have any internal adjustments.

If you mean by color balance that either of the three main colors are too strong, you have to replace IC101 lm1203 as this ic does all of the color processing. Check pins 4-blu, 6-grn, 9-red, for signal level in and pins 16-red,20-grn,25-blu for signal level out. The voltage levels should be very close to each other in each group.

QUESTION NO. P41202-9: Acer 7277c monitor with a burned R356, I need the value.

On my cct for Acer 7277e r356 is 10k and connects to the base of q322 which is concerned with the ABL control. The other side of the resistor goes to pin 8 of fbt

QUESTION NO. P41602-4: Acer 7277e Monitor. I need the value of R339, which burned.

Rr339 is 3.9k 1%.

QUESTION NO. P 43002-8: Tiny A1770NSL monitor, the screen is too wide and bowed but cannot be altered . Electronically altered but controls have no effect . All other adjustments are o.k.

If this "Tiny" model is a LiteOn chassis (FCC# H4ICM17007), try checking Q423 and R411.

QUESTION NO. P43002-7: Mitac L1564PD monitor. Transitor Q502 was removed by previous repair workshop. I need the value of this.

In the Mitac manual's parts list, Q502 is given as 2SD921.

QUESTION NO. P43002-4: Dell D1025TM monitor, how do I adjust the screen controls , and the gain for the red, blue, green, (there are no pots). Is this chassis a Sony? What is the Sony Model?

This Dell is similar to the Sony CPD-200GS model. Service adjustments in that Sony model are done with the Sony DAS software and interface adaptor. Using the user OSD controls, brightness and color temperature levels may be selected.

QUESTION NO. P43002-3: Sony CPDE200 monitor has two horizontal thin, very faint lines running the full width of the monitor spaced about 100mm apart.

This sounds like the stabilizing wires for the aperture grille inside the CRT. These wires are a normal item, and are described on page 13 of the Sony CPD-E200 User Manual.

QUESTION NO. P41202-4: Magitronic C-SV1700PS FCC H4ICM17005. I need part # for HOT Q424 and D407 also, where can I order the EEPROM I703 and the parts above mentioned?

That FCC number is a LiteOn, and in that FCC, the HOT is 2SC5150 and D407 is a Sanyo DD54RC damper diode. Nationwide (www.neiparts.com) or B&D Enterprises (www.bdent.com) may have these. Also, if the HOT had shorted, see if there is an open 2 Amp microfuse on the board. Try asking Nationwide about sourcing the LiteOn Eeproms.

QUESTION NO. P41902-6: Techmedia TCM-1448G monitor FCC j4RTCM1448G. I needed part number for Q507.

Q507 is BU2508DX; a BU2508DF could also be used.

QUESTION NO. P41502-6: Compaq V500 model 1111 monitor has a pulsating picture with poor focus. Turn up G-2 then back down the picture stabilizes. If unit is turned off, then back on the picture pulsates again.

Replace all capacitors with 100v to 250v in H. section and resolder all h. out & v. out areas.

QUESTION NO. P41602-6: D2026T Ultrascan 20tx monitor has horizontal shake after about 1 minute of warm up.

Resolder all capacitors, TR, Diodes near flyback. Resolder crt board.

QUESTION NO. P40202-7: Trigem monitor, without the HOT soldered (I unsoldered from the board) the voltage (b+) on collector HOT is normal (110 to 130 Volt) but when I soldered that HOT on the board the B+ on collector HOT and on the power supply dropped into 30 Volt. What is the real type of this HOT? Is it C4762 or C4770?

Faulty FBT or Short pf in H. section.

QUESTION NO. P41802-2: Gateway CPD-GF100 monitor has a foldover at bottom of screen. By adjusting vertical position the foldover increases when lowering displayed image. It appears as though image was a sheet of paper curling upward from bott m reversing what is on front of the reversal. By adjusting vertical size it will fit but with a tenth of the screen black from bottom of image to bottom of screen.

Replace all vertical out put capacitors and resolder all joints in vertical section.

One cause for this symptom, is a bad C653, a 470 uF/25V capacitor.

QUESTION NO. P41802-10: Proview ps508 model 564px monitor FCC ije-564 is dead. Replaced blown C635 (22 mf cap 250v) and shorted D675 with no change.

Replace all caps with 250v near flyback and check dry sold joint. Resolder flyback and all pf.

QUESTION NO. P326-7: HP ultra VGA 1280 monitor has no picture. The flyback and horizontal output are ok.

H. oscillator IC faulty. Replace and also check 220pf with 2kv.

QUESTION NO. P320-2: Compaq v75 monitor, picture jumps up and down fast. When adjust g2 it stops. Switching it off/on, same problem again.

Resolder vertical section carefully and replace all vertical output capacitors, especially main b+ of vertical output IC.

QUESTION NO. P319-5: NEC/Multisync 2A monitor, is dead. Green LED on front panel does not light. Clicking sound coming from power switch. Fuse is OK. Resistors, caps and diodes all check out. No signs of heated components other than Q502.

Normally H.OUT transistor faulty, replace with BU2525A or BU2508A and resolder all areas of FBT.

QUESTION NO. P41602-8: Acer AJ15 monitor FCC AMPJ511 the display has become very unstable, it changes in horizontal and brightness cannot be adjusted.

Check for dry solder on the crt board. Also resolder all connection joints with main board.

QUESTION NO. P41802-8: Daytek dt1536d monitor- ht arcing from top of lopt to core blowing hot. All other components seem ok.

I suspect the flyback (LOPT) is bad, and needs replacing. This model is also known for getting bad solder on the flyback connections, which also can cause the HOT to blow. A general solder check is needed, as bad solder can occur all over the board.

QUESTION NO. P41802-6: Acer 7178ie monitor. Found components blown Q321, Q314, R363, RF3959, etc...need value of R363 and if possible loop diagram of flyback. Resistor cooked but not obliterated, codes unreadable now showing 12.7 ohms.

In the Acer 7178ie file at rv6llh.rsuh.ru/shema.htm, R363 is given as 22 ohms, 5 Watts; it's in parallel with a coil and a cap. There is an FBT diagram in the Acer 7178ie file.

QUESTION NO. P41702-9: KDS VS-F14 monitor goes dim to almost black within seconds of power on.

Sounds like a component is starting to fail on the inverter board, that provides the high frequency/high voltage AC for driving the fluorescent lamp. Unless it is something simple, like one of the film capacitors on that board is failing, you might prefer to inquire from KDS as to price/availability of a replacement inverter board. Less likely, since it initially lights, the fluorescent lamp itself is marginal/bad.

QUESTION NO. P41702-5: HP D7480A monitor with wide screen and no horizontal size adjustment. On-screen display works and shows that the adjustment is being made but the picture doesn't move. Checked B+, +5 & +12. All are ok.

HP is notorious for using the same model # with different chassis, so check if yours has a Tatung C7B chassis code. If so, dual rectifier D434 (DMV32) is probably leaky, and should be replaced. Less likely, transistor Q470, or IC401, has gone bad.

QUESTION NO. P41602-9: Intex TN1473-8 (Jean) monitor FCC AMP JK1470. Vertical frame collapsed to a thin horizontal line.

In a Wen-brand unit (same FCC#) with the same fault, U201, D201, R206, R207, and R210 were defective, so try checking those components in your Intex-brand.

QUESTION NO. P318-3: How do I set the color balancing on the Samsung 400b, 450b, 550b, 500b, as well as the Compaq V75 monitors? These monitors do not have internal adjustments.

All the Samsung monitors made in the last few years need a "Softjig" to do any setup. This is a computer interface along with the appropriate software that allows you access to a factory settings. You can get this from Samsung. Sony uses a similar setup called "DAS".

QUESTION NO. P40802-5: Mag DX-17F monitor with R501 removed, I need to know the original value. I checked and replaced as necessary all the common stuff for this chassis (including L105).

R501 is a 2.4K ohm 1\4 W resistor.

QUESTION NO. P41502-10: Viewsonic G810 monitor will not adjust fully bright. Osd window ok but screen dull.

There are at least four versions for G810, but if given no suffix, I will assume this is FCC# GSS21001 (HV8 chassis). If the OSD is good, then probably this unit needs re-adjusting, using Viewsonic's alignment software (get this from Viewsonic). But if you are running this unit on a test bench with a video splitter, try driving it directly, first, as sometimes these have brightness problems using a video splitter.

The chassis # is 21VS001. Update on monitor is that after a few minutes of running monitor screen now goes blank. Osd still operational although slightly out of focus. Checked heater voltage and it reads just over 6.0v. Suspect possible problem with hybrid crt driver on neckboard(VP3628-1). Need pinout for this ic and substitute/replacement if possible.

QUESTION NO. P41102-2: AppleVision 1710 monitor M2935 sn/ SG5463P565J is failing to display the red portion of the video. It does include the red gun output in the default OSD boxed brightness/contrast adjustments so I believe the problem may be in the CRT video board. The video signal cable has checked out O.K.

Use apple machine with monitors & sound control panel or applevision software 1.5.3 or later which gives you the ability under color tab to recalibrate the monitor. Apple recommends trying at least 6 times to recover the board. If not, remove the cover of the video board and resolder the three transistors but be sure to connect the after thought wires coming up through the holes or it will not fire up.

QUESTION NO. P40802-4: Acerview78ie monitor with a horizontal collapsed (top to bottom).

Replace TDA8351 vertical IC and check C368 22nF 2kv cap also.

QUESTION NO. P41202-3: Samsung MDL. 750s monitor chassis DT17L. Q404 horiz has house nos. C5802 not available what is real replacement number? D406, what is replacement number?

In the schematic, Q404 is KSC5802 (Samsung/Fairchild). This is not really a house number, for this device is publicly-offered. Possible substitutes might be 2SC5299 or 2SC5387. D406 is ERD07-15 (Fuji Electric); a possible replacement is a Philips BY228.

Transistor Q404 is not 2SC5802 but KSC5802 by Samsung. Samsung part number is 0502-001129. It is a common failure part.

QUESTION NO. P312-9: Sony CPD17SF2 monitor, high voltage comes on for about 30 sec and then shuts down. Both leds are blinking. HOT and fusible resistors are OK.

Q510=HV reg o/p transistor is nearly shorted, about 200 ohms and must be replaced, Sony # 8-729-033-93 located in D board.

QUESTION NO. P41102-3: NEC Multisync 70/pn 7701 monitor. Three months ago replaced F101, Q101 burnt, ZD101 shorted, C119 burnt when Q101 blew, C156, and U101. Now F101 blew and Q101 and ZD101 shorted again.

If Q101 and ZD101 shorted, you should replace U101 once again; also check on the condition of TH101, the 4-Amp inrush current limiter. TH101 should be roughly 5 ohms when cold (25°C). These units can get bad solder on the board, so check/repair solder, and they get bad caps, incl. C107, C117, C121, C122, C156, etc, so check generally for leaky or open/shorted caps. There is also a stand-up resistor there, near a diode on a heatsink, that will short out Q101, if its lead touches the heatsink. If Q101 still blows, try ringing the SMPS transformer primary.

I found filter C105 across the bridger no good . Replaced it along with Q101, Zd101,and U101. TH101 read 5.5 ohms, but replaced it anyway.

QUESTION NO. P41102-9: Proview 986M monitor, FCC IJE986 will power up ok without signal applied. Once signal cable is connected monitor will shut on and off rapidly. Now will not power up at all, have checked for the usual type of failures and shorts but so far no luck.

Check D632, C635, Q630, Q65A, and R65B (47 ohm). D632, in some units, is a pair of rectifiers, and D632 may test good when it is not.

QUESTION NO. P329-5: Apple Multiple Scan M2943 monitor, the customer said it made a pop, then smoked. It was showing a line up the middle of the screen. I found R410, R475, C416, and Q418 burned beyond recognition, I need the values.

R475-68 ohms, C416-514J mp250v, Q418 K1035. In the two chassis I have, there is no R410.

QUESTION NO. P41002-5: ADI LM1764 monitor (Microscan range) FCC BR8LM-1764, the display has become very unstable, it changes in width / height as brightness / contrast are adjusted.

Try checking C851 = 47 uF cap. Replace with a 250 Volt, 105° cap, if possible.

QUESTION NO. P40902-8: IBM G74 monitor. Photo transistor OP601 PC123 (made by Sharp) and video driver LM2405T burnt. What is a reasonable substitute for PC123?

The Sharp PC123 optocoupler resembles an NEC PS2501-1. This NEC device is listed by Mouser (www.mouser.com) and Digikey Corp (www.digikey.com), among others.

QUESTION NO. P40802-6: Sony GDM-500ps monitor with vertical centering problem.

Check IC007 = CXA2043Q (Sony p/n 8-752-078-46), it is a known-failure chip. Note, sometimes DAS alignment is needed, after replacing IC007, so you might first check IC702 = LA7841L, and its surrounding components, before replacing IC007. If you do not have DAS, you might send this to a Sony-authorized shop, for the alignment.

QUESTION NO. P40502-7: TVM as6s monitor has no image, power supply in protection. I changed the line driver 2sc5148 for a bu2525af. The image is now too wide and the adjustment button does not work.

First, check 3 Amp ultrafast rectifier D406, and transistor Q424, for reverse leakiness or short. If these are OK, check coil L413 for shorted windings.

QUESTION NO. P40202-1: Proview PV-850DM monitor, need value of R623, R666, R637 and R634. All burned beyond recognition.

Proview model numbers are ambiguous, but if the FCC number is IJEPV-564D, I show R623 as 4.7 ohm (fusible); R668 as 150K; R637 as 10K; and R634 as 2K. In that circuit, if these resistors were burned, I would suspect a defective flyback transformer.

QUESTION NO. P40402-10: Mercury D7032ND monitor. I need a sub for IC109 (5S0965).

The full number for that IC was KA5S0965, formerly manufactured by Samsung/Fairchild. Fairchild (www.fairchildsemi.com) has replaced it with their newer IC, part number FS6S0965R, which is currently available.

QUESTION NO. P40302-8: AOC Spectrum 4Vlr monitor has no +12V on output of regulator, on Q909 E = 14V, C = 0V output to IC904, B = 0V (If I open J041 = 14V). Replaced Q909, IC904 and surrounding caps.

I believe Q909 will not turn on, unless activated by Q910, and Q910 is turned off by the "suspend" mode pin, of the uProc IC. That is to say, the uProc has shut down this monitor, by turning off Q910 and Q909, and so Q909 is not the source of the fault.

QUESTION NO. P327-8: Apple Colorsync M3705 monitor has no H.V. in the EHT (ZL4). SMPS seemed to be OK and have following voltages on the secondary windings of the ZP1 (200, 85, 30, 12,6 Vdc). After start-up there are neither supply has driving pulses on the QL11, QL23, QL6. MOSFET's QL2 and QL12 have app. 200V on their gate and source leads. How can I check EHT? I replaced TDA 8172 without solving my problem.

HV will not come up unless it gets the signal from apple CPU or Soncor unit with adapter. If you have either of these then the processor on the video board gives the signal to the MOC2A60-5 opto-isolator which in turn switches on the bridge. Common faults include RL83, RL59, QL2, QL23 & 22 ohm resistor close by or RP49 can affect the start up sequence. If these fail to operate the HV will not come up RP49 is a PTC thermistor that either burns or goes open, check all solder joints as well and make sure the video board ground wires are not broken.

QUESTION NO. P40202-5: NEC Multisync 6FG monitor. The led is green, when I turn on click, click (about 5 seconds, the Led is blinking) and then the led is normal. The HOT (C3998) is too hot and then burnt, I guess that the HOT (C3998 ? Volt, 25 Amp, ? Watt). Can I use C3997 (20A) to change the C3998? Or can you tell me the equivalent of C3998?

The 2SC3998 should be readily available, but 2SC5047, 2SC5444, or 2SC5453 might substitute. I don't recommend using a 20 Amp HOT, to replace a 25 Amp HOT. If your HOT was too hot, check or replace Mosfet Q5G6, it is probably bad. Also check capacitors, like C571, C572, and C573.

QUESTION NO. P40202-8: Iiyama VisionMaster PRO 21 Model MT-9121 monitor with burned HOT. What is the best replacement?

My notes show the OEM HOT in MT-9121 to be 2SC5045, and original is always "best". Since this is a 1600V HOT, substitutes are limited, but 2SC5451, 2SC5588, 2SC5553, or 2SC4896 might work.

QUESTION NO. P40102-10: Apple 750AV M2935 monitor. I need values for RP49 RP3, DP17, IP2 DL23.

The RP49, on the board I checked, had no markings, and was not a typical resistor, but appeared to be a custom-made item, in a small white plastic receptacle. The RP3 = 2.7K ohms; DP17 = 1N5931B (18 Volt zener); IP2 = LM431ACZ (same as TL431); DL23 = 1N4148 signal diode (if you really meant large transistor QL23, that was MJW16206).

QUESTION NO. P40102-5: Proview 772M monitor. I replaced a burned JFET Q630 (Irf 634) and the monitor works well but it burns again after plugging the cable for the computer. I change the JFET for a equivalent . I checked all caps but all is good. I cannot find the IRF 634a .

First, IRF634 is a Mosfet, not a JFET. Digikey (www.digikey.com) is one source for IRF's IRF634 (Fairchild's IRF634A is not much different, electrically). You might be able to use IRF740 or IRF740A, if you cannot get IRF634. Besides Q630, also replace the 3-Amp ultrafast diode, D632, and 250-Volt capacitor, C635, regardless of any testing. If there were any ferrite beads on the legs of Q630, be sure to retain them.

QUESTION NO. P40102-9: Gateway 700-069cs monitor FCC BEJCS789 with no display. HV ok, heater ohms out fine, no OSD, unit powers up fine seems to be running, but has no illumination. Plug P904 PIN 5 is supposed to be 6.3V, but is riding at 12V. I tried the easy stuff, soldering, checking for dry caps, etc.

If the heaters are getting no voltage, and their supply has no load (6.3V rises to 10-12V), sounds like a bad connection. First resolder R370 (0.22 ohm) on the CRT board, regardless of how the solder appears; this is a very common fault. Also check for bad solder elsewhere on the CRT board and the CRT pins. The filter cap C922, if not one of the ones you checked, should also be checked.

QUESTION NO. P31-9: Gateway EV700a monitor CA-65 chassis made by LG/Goldstar, P/S hiccups for 5 seconds, then HT is Ok at 160V for 5 seconds, then hiccups for 5 seconds etc. Perhaps there is a short in the line stage but everything checks out ok.

A common problem is a bad flyback transformer, 6174Z-1012, but you might also check the voltage regulator IC's, IC923, IC925, (and IC304 on the video board), as well as their solder, & check dual diode D704 for any reverse leakiness or shorts.

QUESTION NO. P329-3: Acer 7154e monitor, C326 is open circuit, FET Q317 is shorted L304 is shorted. C335 seems OK, R214 is fine as are Q310, C319, D316, D317. I replaced the faulty FET Q317and coil L304, but the FET still blows.

Assuming C326 was also replaced, that all the other components mentioned are still good/correct value (a bad C335 or D317 won't always test bad), and the new L304 has not been damaged by the repeated shorts of Q317, then I would also check C317, the damper D307, and ring the flyback and horizontal yoke, in case of an excess load. If it is not this, I would check the components for the feedback control of the B+ circuit, including IC201 (TDA4858). The flyback should create a +40V output, using R323, D304 and C306, and this connects via R220 (68K, 1%), R216 (100K, 1%), plus C237 and C205, to pin 4 of IC201. If not this, then check components in the gate drive circuit for Q317, coming from pin 6 of IC201.

QUESTION NO. P328-1: Smile CB6919SL monitor was blowing the main fuse. Q506 (p/n K2828) in the power supply is shorted out. s I cannot find a cross ref # for it. Is there any thing else I should look at before I replace the transistor?

If your Mosfet had shorted to its gate, check/replace components off the gate lead, like resistors, diodes, and the driver IC itself. You might also ring the SMPS transformer, in case it had a shorted winding that blew the Mosfet. The 2SK2828 (Hitachi) is a 700 Volt, 12 Amp, 1.2 ohm, 175 Watt Mosfet. What makes it hard to cross, is that its gate has built-in zener protection. If there is already a gate-to-source zener in your Smile's gate drive circuit, this feature is not really needed, and you might substitute a plain Mosfet, like STW11NB80 or 2SK2477. Also, besides 2SK2828 itself, gate-protected Mosfets like STW9NC80Z, FS14SM-14A, FS10SM-18A, or FS10SM-14A, might be possible crosses. Or, you could install your own gate-to-source zener (18-20 Volts, 0.5 Watt), and use a plain Mosfet, like the STW11NB80.

QUESTION NO. P327-6: HP D5458A monitor Chassis Code C5B has a blinking green led along with the clicking of SR801 (degauss relay). I believe the problem to be in the power supply. I862 (UC3842B) voltage on pin 7 varies between 10.4-15.1 VDC. The leads on D807 appear discolored but the diode appears ok.

I don't know your HP D5458A model, but one of the several chassis installed in the HP D5258A model is a C5B type, so maybe it is similar. If so, first check the components for the running supply for the 3842 chip, going to pin 7, consisting of a winding off the SMPS transformer, then two consecutive sets of diodes with electrolytic filter caps. If there is a fault here, your 3842 may try to start up, but will not have enough current to stay running. Also, check the filter cap off D807, for low capacitance, or leakiness, and check for bad solder on D807 and that cap. D807 & its filter cap provide the 8V supply, for both the heaters and the 5V regulator for the micro, so if the 8V supply is poor, the micro could be having voltage problems when the heaters draw their initial current. If these are OK, perhaps an overload on one of the secondaries, if severe, might lower all the other transformer voltages (including the 3842 running supply), to cause the 3842 to start pulsing from undervoltage.

QUESTION NO. P326-1: HP d2835 monitor FCC a3lcge750 screen is wavy or flickers continuously every time a full bright window screen is maximized but not at minimized. The image will remain normal, only the brightness affected.

In the Samsung 700s (same FCC number), a bad C517 (a 3.3 uF nonpolarized cap) can cause flickering that is affected by brightness. C516 might also be checked.

QUESTION NO. P37-6: AppleVision 750 (M2935) monitor had no operation, repaired dry joints on FBT & in horizontal circuit. Ran for about 5 minutes then stopped. Now at power on LED blinks green then goes out. SMPS not running?

Check MOC2A60-5 solid state relay then QL2 then RL59, RP49. If not, you may need Apple software to upload data to video processor in gun board.

Check all listed here previously and also IP1 (TDA4605-3) PWM controller. Replace CP9 also & check the other two electrolytics nearby.

QUESTION NO. P320-9: DTK M/N DA-456 BA monitor. I need the value for C441.

220pF 2kV. You'd better put a 220pF 3kV there.

QUESTION NO. P322-3: Zenith ZCM-1450-UT monitor, horizontal line in the center of the screen. I changed vertical output IC LA7838 but no use.

Replace vertical filter caps as they could be the reason why LA7838 went in the first place followed by the fuseable low ohms resistor at pin 1 & 8 (VCC pins for LA7838) leading back to a rectifier diode which leads back to the flyback x-fmr.

QUESTION NO. P322-2: Viewsonic Monitor P810, within 2 seconds of power on, it goes to suspend mode and it's light changes from green to orange. I checked all horizontal transistors and power circuit, nothing seems wrong. I looked for dry solder.

Try unplugging any new USB peripherals that you have and then see if it comes on. It may be that is has the wrong USB cable on one of the peripherals.

QUESTION NO. P319-10: HP D2835 monitor FCC A3LCGE750, all the osd controls work except the pincushion control. The screen is bowed in a lot and when I go to adjust it, there is a very small movement in the screen. I have scoped a signal going into Ic 401 pin 3.

C443 3.3uf/50v NP

QUESTION NO. P318-6: I need the cross reference for transistor Q801 p6n60f of a Viewmate pwb-1402 monitor.

Possible crosses include NTE/ECG 2379, or IRFBC40, with insulator; 2SK1118, 2SK1507.

QUESTION NO. P314-11ViewSonic monitor P817 VCDTS21410-1. Deflection board PBH176-4 replaced with PBH176-6. Horizontal size at low resolutions is too small. Using software H.SIZE MAIN (DAC F/V2) can be set but can't be saved using supplied password. H SIZE LIMIT at high resolutions can be saved without problems. Any idea about hardware changes or data DAC F/V2 saving?

Horiz size at low resolutions can be saved into "HSize Max Mac480L" window under SIZE LIMIT menu.

QUESTION NO. P313-1: Optiquest 4000DX (Acerview 7076) monitor. I need the value of r378 in the Horizontal circuit. It fried and obliterated the bands.

In the schematic for Acer 7076i, R378 is shown as 15K ohms.

QUESTION NO. P313-8: Daewoo monitor 710B chassis. Need value for R939. Too burnt to read.

The 710B manual lists R939 as 100K ohms.

QUESTION NO. P213-5: HP D2835 monitor FCC A3LCGE750, need value of R420 in horizontal scan circuit.

R420 is a 680 ohm 1/2 watt FP.

QUESTION NO. P312-6: KD-1700V monitor from KDS. Q404 burned out. I need the type of this transistor please!

Q404 is 2N7000, a small N-channel Mosfet. The 2N7000 is made by many manufacturers, including Philips, General Semiconductor, Fairchild, ON Semiconductor, Vishay, etc.

QUESTION NO. P311-4: Panasonic Panasync S110 monitor. The HOT 2SC5423 and transistor Q881 2SJ306 were shorted. I changed them and now I have the HV but there's a single vertical line at the screen, probably the horizontal deflection. I checked for bad solders or components but everything seems to be fine. I checked the yoke coil with an ohmmeter and that's fine too. Could it be the horizontal deflection transformer? With an ohmmeter, all the pin on the primary have low resistance between them, same for the secondary.

Q550 is only for horizontal deflection. Check if its B+ resistor, R890 = 1 ohm, has also opened up. Aside from the B+ resistor, there should be DC continuity between the drain of Q881 and the collector of Q550, through the inductors. If this is OK, check if Q549 and IC580 are good, and providing drive for Q550. Also check the associated electrolytic caps, C551, C578, C859, etc.

QUESTION NO. P218-10: Mag dx700t monitor, the flyback is giving too much voltage to the CRT connector. Two of the cables that come out of the flyback, one red and other white, make 1.5 inches of spark, like the other cable that is connected to the screen. I checked all components from answers in your database, and they are ok.

If the other voltages are correct in the Horizontal deflection circuit, replace the flyback.

QUESTION NO. P220-8: Dell Ultrascan P780 monitor appears to power up, No green / amber light. Fuse OK. 120 through the fuse.

Check the Horizontal Output Transistor. It may be Open, or otherwise failed.

QUESTION NO. P225-2: Mag DX700T monitor. I need the value of R173, it has burnt the color off.

The Mag DX700T model has a couple of different chassis versions, with different FCC numbers, but I think your chassis version is the one where R173 is 10 ohms.

QUESTION NO. P129-2: Sun/Sony GDM - 20D10 monitor when cold starting the red color gun is missing then after 30 seconds the red color gun appears. Also I need information on boosting or rejuvenating the crt (GDM -20D10) using a video display tester, Model 490 by BK Precisions. I require information on how to connect the crt socket pins of the video display tester to the correct crt pins of the monitor (i.e. G1,G2, Heater etc).

I've restored these CRTs with a Sencore CR70. I had to do a little homework to get the CRT pinouts
4 G1 Green (at 8 o'clock position next to keyway)
5 Heat
6 Heat
7 G1 Blue
8 K Blue
9 G2
10 K Green
11 G1 Red
12 K Red
13 NC
Heater is 6.3V, Bias is -36V for a M49KZK15X CRT

QUESTION NO. P129-7: KDS VS-7 monitor FCC EVOKD-1730. Need part numbers for R463, D408, Q408. There were many caps with the tops blown in the power supply and around Q408. The unit is making a ticking.

There were a lot of bad caps, too many to mention but a few in the power supply and the rest in and around these parts - R463 4.7k , Q408 IRF630 , (D408 IN4148 <-Not sure about value) also IC801 UC3843AN was bad which kept the unit from firing up. I still have a problem with what looks like a spiraling rope vertically on the screen.

QUESTION NO. P225-9: Two HP monitors D5259A with R451, R452, R443, & R 443 burned too bad for identification. Is there a specific cause?

First, there are several different chassis that HP has installed in D5259A, from different manufacturers. You need to provide a FCC# or a chassis code, to help pinpoint the one you have. IF your chassis code is C7B (Tatung chassis), my schematic for the Tatung C7B shows R443 = 1K, R451 = 1.5K, R452 = 1K. Also along the same circuit, are C451 (1uF/250V), C323A, C326A, VR321 (20K), R320 (3.3K), R325A (2.7K), and IC401, so these could be checked for damage as well. I would also be suspicious that the B+ regulation circuit and/or the flyback, is bad.

QUESTION NO. P225-3: Apple Scan 1705 monitor (Goldstar chassis CA-24-6) no sync. if I remove the memory 93c46, it synchronizes. I need information on the memory 93c46 to program it.

The Apple MultipleScan 1705 is a Goldstar chassis, and the Goldstar Eeproms are programmed while the unit is running, using a special Micom jig. If you know someone at a nearby LG-authorized shop, inquire if they will program a new Eeprom chip into this chassis for you. They would need to know if your Apple 1705 is an M4436 or an M4502 model, to find its listing in their Eeprom library from LG. Be assured, that Apple itself will NOT be helpful.

IC is serial memory, try National Semiconductor or Microchip (Arizona microchip) websites. Be warned programming not simple.

QUESTION NO. P131-4: Peacock PM17P64LR monitor. Need a value of R458. After replaced Q311-2SC4542, Q313-TIP 47, Q312-2SD669 and R458(replaced with 15 Ohms) monitor runs, but the H-size is too small. After a few minutes the voltage on R458 (current of the deflection part) increase faster and faster, then I turn off the monitor before Q311 blows again. During the current increase the supply voltage also increase. If I reduce the H-size with the control buttons monitor runs longer until the current start to increase. I replaced C389 and other capacitors in the deflection part but without success.

Without having its FCC number, I cannot be sure, but your description of this Peacock model sounds like a version of an Acer 76i (FCC# JVP7076I or JVP7176I). The value of R458 is given as 2.7 ohms, 3 Watts, in the Acer 76i schematic, but different 76i board versions are seen with values of R458 ranging from 1 ohm to 3.3 ohm (but not as high as 15 ohm). I would resolder the horizontal yoke connector, and M605 power supply connector, and also check value on R239, R243 (0.5 ohm, 1/2 Watt; some versions use 1 ohm), and R456 (150 ohm), and caps like C341, C343, C390, C391, C395, besides the C389 you mentioned.

QUESTION NO. P220-2: MarkVision monitor FCC AMPJD144, Q418 (a mosfet k2134) is very hot and tests short. I replace it with 2SK1117, still very hot. What is the exact replacement of K2134?

The exact number for K2134 is 2SK2134 (manufacturer NEC). The 2SK2134 is similar to IRF630.

QUESTION NO. P220-1: Viewsonic g810 monitor chassis 21vs001 powers up (green light) but no HV. The switching supply is running and there is drive to the HOT. Damper diode is good. B+ is good (75vdc)to pin 8 of the FBT. I cannot find a connection from pin 10 of the FBT to collector of HOT.

The FBT is driven by Mosfet Q610; Q550 (bipolar) is the HOT for the deflection yoke. I believe a diode, D602, isolates the FBT from direct electrical continuity with Q610.

QUESTION NO. P26-9: KDS VS-7e monitor, when push any control button, the video disappeared and can hear relay ticking sound. Then video is back. CPU is LSC506406B. I doubt CPU bad.

You have a problem with the EEPROM- small microchip 8pins beside microprocessor. It has to be replaced with new one or reprogrammed. Common problem for many models.

QUESTION NO. P220-6: Acer 76i monitor has a slight jitter or pulling on the outer edges of the screen. It is very slight at 640x480 but the higher the resolution and refresh rate, the worse it gets.

You probably have bad capacitor. Check small cap like 220pf/2kv value connected to HOT collector. It is common problem with Acer monitors-bad design. This cap may look like burnt slightly. Better replace that cap with two caps in series connection. Sorry I do not remember position number of that cap.

I believe it is the Acer 76ie model (not Acer 76i) which has the problematic ceramic disk cap off the HOT collector. In the Acer 76i, first check for cracked solder on the M605 power supply connector and horizontal yoke connector, re-flowing if needed, and for bad solder generally, and check the ESR on C631 in the power supply. If this is not the cause, check IC311 = TDA9102C and its surrounding components; try heat/freeze to test it, or replace the IC.

QUESTION NO. P219-1: Viewsonic 6E monitor appears completely dead. There is supply voltage into the power supply with other power supply voltages present. However, it does not fire up , there is no l.e.d. on switch on , capacitor C605 stays charged (ouch).

I managed to locate and repair the fault. There are two 33k 1w resistors in the power supply circuitry. One of them had gone open circuit.

QUESTION NO. P213-4: Have a rash of Sony built Silicon Graphics GDM-20D11 monitors with a wavy herring bone like pattern in the video. It is best viewed with just a white raster. Problem appears to get better as unit warms up. Have traced problem to deflection module by swapping out boards. Suspect leaking caps but can't seem to find the problem.

Despite that swap, the most common cause of herringbone in the Sony P4 chassis is bad caps on the A board. If you have many units with this problem, I would check those caps. Most commonly, bad ESR in the filter cap for the video amp supply allows noise to enter the supply. In a GDM20D10 chassis here, that cap is C13, but others include C14, C15, C24, C71, etc.

QUESTION NO. P124-5: Hewlett Packard D2830A monitor has no power, no light, just a ticking sound.

Check HOT transistor - probably is shorted and power supply cannot start.

QUESTION NO. P212-7: AOC 7G1r monitor, I need a replacement for SUF5402? D921.

This will be a 200 Volt, 3 Amp, ultrafast rectifier. Possible substitutes include SF34 or UF5402, available from suppliers like Mouser Electronics (www.mouser.com), or NTE/ECG type 588.

QUESTION NO. P211-9: EMC Proview 768M Monitor FCC 1JEPV-768. I need values for R520, R521 and C520 burnt beyond recognition.

R520 = 22 ohms, R521 = 47K ohms, C520 = 0.01 uF.

QUESTION NO. P211-10: CTX 1760LR monitor smoked R438, I need the value and any related components that may be damaged.

R438 = 100 ohm, 5 Watt. Also check Q305, Q412, D410, R353, C308, C423, and check a 47uF/250V electrolytic cap (C135 or sometimes unmarked), at the back, near L104.

QUESTION NO. P28-10: HP D2825 monitor, led blinks and no picture. Q317=2sk2161 is burnt.

You should note that the FCC# of HP D2825 is JVP7154E, indicating that this chassis is like the Acer 7154e. Check Q310, C319, C326, and replace ceramic disk cap C335 (220 pF/2KV). If C335 is discolored/bad, check if R214 (15K) & IC201 are defective. Check if coil L304 has shorted/burnt windings, or if its inductance has dropped much below about 0.6 mH; if yes, replace L304, or Q317 will die again. Also check if D316 and D317 are leaky in reverse.

QUESTION NO. P25-8: WEN JD177P3 monitor keeps blowing Q407. It gets hot after a few seconds and goes belly-up. Repaired supply (few minor problems). B+ is 220V. Also replaced Q410. Would an IRF740 do as substitute for Q410? Who manufactured this board?

The JD177P3 number sounds like a chassis from Jean Corp., Ltd. An IRF740 seems reasonable for Q410, although IRF740A (less capacitance) would be a bit closer to the original type used. A B+ of 220V sounds too high, so you might check components off pin 2 of the 3842 chip (off-value resistors, etc) in the power supply, in case one of these components is causing the secondary voltages to regulate too high.

QUESTION NO. P26-6: Digital-pcxbv-pc monitor. I am looking for info and possible replacement for a HOT made by Motorola and marked "LJH16212".

The FCC# for Digital PCXBV-PC, A3KM046, crosses to a Philips chassis, and LJH16212 is Philips part# 4822-130-62701. LJH16212 might be replaced by the similar MJH16212, so for specifications, refer to the specs in the MJH16212 datasheet, available at http//repair.vist-v.ru/ds/transistor/bipolar/MJH16212(MJF16212).pdf Nationwide (www.neiparts.com) is listing MJH16212, probably the closest one. Besides MJH16212, MJW16212 might also be tried, assuming its TO247 case will fit. MJW16212 is the currently-produced version; LJ Enterprises (www.ljent.com) is a possible source.

QUESTION NO. P117-10: Daewoo 712D monitor. When powered off, vertical blue line, and then blue spot. I changed the Flyback.

Check G1 & G2 lines to video for broken or bad joints, also check vcc line to flyback for partially open resistors, check all components on this line.

QUESTION NO. P118-1: HP D5258A M50 monitor. I need the value of R415 which was burnt out after replacing R024 (2.2M ohm .5W). The original fault was dead.

R415 10 ohm 1w.

QUESTION NO. P25-2: Viewsonic P810 monitor with a power problem. I found IC S6531 not responding. I need the value and/or an equivalent.

Viewsonic has several chassis versions for P810, but I will guess that your P810 is FCC# GSS21001, which is a Panasonic 21HV8SA chassis, in which IC820 is STR-S6531, a Sanken regulator IC. For this IC, you might substitute a STR-S6531A. Try Nationwide (www.neiparts.com) for these IC's. Less likely, your P810 might be FCC# GSS21010, which is a Panasonic HV10S chassis, in which case, your IC might instead be IC580 = AN6531.

QUESTION NO. P21-1: LG StudioWorks 44m monitor FCC BEJCH480. I need values for R726, R742, C723 which were burnt. I checked the power transistor which is o.k.

in the schematic, R726 = 10K, R742 = 33K. C723 is only marked as "105" (I presume, 1 uF). From the locations of these parts, check if the flyback transformer is defective.

QUESTION NO. P131-6: Compaq v90 monitor was dead. Repaired power supply, replaced shorted q831. Starts up but no HV.

Besides Q831, also check/replace FET Q563 and R866 (2.2 ohm), and test the flyback transformer. Also, detach the flyback's HV anode lead from the CRT, and check the resistance from this lead to deck. Any resistance less than infinite, that appears on the x10K resistance scale of an analog-VOM, indicates a defective flyback (LZ250A000P, or FEA662), that must be replaced.

QUESTION NO. P130-2: Dell D1226H monitor FCC A3KM073 has no video. Found Q7543 (MTP5P25) shorted and R3544 burned. I need the value for R3544.

R3544 = 1 ohm, 1/4 Watt, fusible. Also should check Q7532, D6534, and L5526.

QUESTION NO. P129-1: Gateway monitor EV900. What is the current, voltage, and recovery time on D315?

D315 is rated at 3 Amps, 200 Volts, and is an ultrafast type (Trr < 50 nanosec).

QUESTION NO. P125-8: HP2837A monitor FCC A3LCKB722, the FBT (numbered T501 on pcb) gives ticking noise on startup, green led is lit for 3 seconds, then it flashes (like shutdown). Both horizontal & vertical deflection seems working. The Q503 seems ok, tried with substitute. All voltages are quite ok, only the +13V gives +11V. Maybe something is loading it. Checked also the IRF740. If I remove drive from the Q503 (2SC5339?) it does not give the ticking noise. Any ideas what to look for next and what is the FBT type, could not find any substitute in my documents? The schematics is quite like Samsung GS450 but there are little differences. Also checked nearly all diodes.

Since Q503 is the HOT that runs the FBT, the FBT may be bad. The FBT type is FKI-17A001 in this Samsung chassis. Nationwide (www.neiparts.com) may have this FBT, or try a Samsung parts distributor. In the UK, you might try PSA Parts (www.psaparts.co.uk).

QUESTION NO. P1228-4: NEC Multisync A700 monitor, the HOT, FET, Q601 (K2645), Current Mode Controller, IC621 (KIA3842P), and ZD601 that goes to pin 6 of IC621 (KIA3842P) are all blown. I need to know the voltage rating for this Zener.

Since ZD601 is off pin 6 (output pin) of the 3842, see if it is a gate-protection zener for Q601, connecting between the gate & source pins of the FET. If yes, the precise voltage rating will not be very critical. Generally, zener values from 12V to 20V will work for gate-protection, in circuits that use a 3842 IC to drive a standard-type FET, like your 2SK2645. Many techs simply use an 18 Volt zener as a universal replacement.

QUESTION NO. P123-6: Compaq V70 Model 621 monitor. I need value of R632.

R632 = 10 ohm/1 Watt, fusible. Also check/replace Q639, C641, R617.

QUESTION NO. P123-7: Apple M3705 monitor has a horizontal deflection problem. I need the value of RL163.

RL163 = 4.7 ohm, fusible. Also check QL2, QL23, and check for any bad connections on the horizontal deflection yoke connector.

QUESTION NO. P122-6: Nokia multigraph 447x monitor I need the value of R205 and a resistor 1/4W between R194 and C121 which are burned. R120 is burned too. What would cause this?

Both R195 and R205 are 215 ohm/0.5 Watt. R120 = 100 ohms. R224 = 0.47 ohm/0.5 Watt, flameproof. Also check FET's T27 and T13, HOT T32, and check inductor M3 (p/n# FM2525 or FM2565) for shorted or burnt windings. Check the yoke and CRT board for bad solder, and for any thru-hole rivlets with cracked solder (both sides). Look on both sides of the board for any tiny SMD transistors that may be bad.

QUESTION NO. P118-10: Philips 107S monitor. I need a readily available equivalent for a mtp6n60 n-channel enhanced power mos transistor. 600v (vdss) <1.2ohms (rds - on) and 6.8A (id). I checked on the sgs-thomson site and it is supposedly obsolete.

There are many substitutes for MTP6N60. IRFBC40 or IRFBC40A (listed by Digikey and Mouser, among others), 2SK1117, and ECG/NTE 2379 are some of more available ones.

This transistor is available from Radionics ( www.radionics.ie ) Herbiton Rd Dublin Ireland or R.S. components in U.K. part no 441-013 for 2.87 euro + vat a p&p it is advised to use buz355 800V 6A 220W on a heatsink for testing a suspect circuit. In a monitor replace any hi voltage caps 1kV and examine electrolytics for leaks.

QUESTION NO. P114-7: KDS VS-7 monitor, if the power button is pressed, the monitor makes a clicking sound and the power LED blinks in sync with the clicking. The noise seems to be coming from the transformer near the center of the circuit board. When viewing the board from below, the board appears to be fried but is relatively isolated. Opposite the transformer is a heat sink where the board seems to have been fried locally as well.

Try checking/replacing Q411, Q408, Q407, and C438, C437, C447, C816. Also check diodes D404, D405, D409, D410, D411, D412 for any resistive leakiness in reverse. If any of resistors R901 thru R904 are burnt, the flyback is bad, and needs replacing.

QUESTION NO. P116-11: Hewlett Packard 2828A (Acer 7254E) monitor, chassis 7254E, FCC JVP7254E has no display, just flashing orange LED.

Saw a lot of previous postings on C335 and area around it in this forum. This only misguided me and cost me 3 days looking at the wrong area! Shorted Q317 (FET) IRF630M (insulated) replaced with IRFIBC40G (for testing); bad HOT BU2520DX replaced with BU2520DF. Monitor now powers up with insufficient horizontal width, and goes into standby mode shortly, more quickly in VGA mode. All user controls work, but still insufficient horizontal. Low reading found on C314 (0.00332uF, 1600 KV pps) of 0.01uF. I had a previous problem with the HOT and FET being blown on an Acer 7211. These Capacitors are always located on the HIGH VOLTAGE FOIL on HOT's collector (can't miss it, the foil has extra solder beadings on it). Replaced. Monitor is now perfect! I also replaced IC 201(TDA4858) but that didn't improve any. So, don't waste your time & $$$ with that one!

The postings involving the faulty disk cap C335, refer to the Acer 7154E model (with FCC# JVP7154E), not the 7254E model, which is different. This sort of ambiguity in the model numbers which monitor manufacturers assign to their units, is one of the reasons why it is helpful to include FCC numbers and/or chassis codes in a posting about a monitor, besides just the model number, and why posting an abbreviated model description (like "Acer 54e", for example), is risky (in case there is more than one chassis out there that could be described thusly), in order to avoid replies about the wrong chassis.

QUESTION NO. P116-5: EMC aka Proview SA560 (564SA) monitor w/shorted TDA blew R307. Need the value of R307.

R307 = 10 ohms/ 3 watts.

QUESTION NO. P116-9: IBM G74 monitor. Opto coupler OP601 PC123 (made by Sharp) and video driver LM2405T burnt. What is a reasonable substitution for PC123 opto coupler?

A reasonable substitute for the Sharp PC123 is the NEC type PS2501, which is carried by Mouser Electronics (www.mouser.com) and Digikey Corp. (www.digikey.com).

QUESTION NO. P114-3: Sony CPD-E500 monitor cannot get the cover off. There are 2 screws on the back and that's it. They were removed and the back half of the cover lifts up but there is something on the top-front keeping it from releasing.

A lot of the Sony's have two locking claws, hiding under the top of the front bezel, a couple inches in from each side, in addition to the screws. These claws must be disengaged, by pushing down on the bezel in front of the seam, just before each claw (or if necessary, by inserting a flat blade at the seam), before the rear housing will come off.

QUESTION NO. P111-6: AcerView 78ie monitor. At resolution 1024x768 bottom half part of monitor is fine top part completely blind and a tiny bright line in the middle of screen. At low resolution 640x480 or 800X600 no images at all on the monitor.

Check/replace the vertical IC, IC201 = TDA8351, and check surrounding components, including the 27 Volt zeners, ZD201 - ZD204, and the values on nearby resistors, not neglecting fusibles RF208 (1.5K, 2W) and RF209 (1 ohm, 2W). I would expect about 54V on pin 6 of IC201, from the zener values.

QUESTION NO. P17-1: Acerview 78ie FCC JVP7178ie monitor powers up with black screen and LED is on green. All correct voltages are available from PS. RF3929 (22 ohm, 3 W) is open. Are C318, C317, C319, C384,C385, C386, D305, Q304 and Q313 all suspect?

Since the PS voltages are correct, it is likely there is a defective/shorted component downstream of RF3929. The most likely culprits on that list are Q313, D305, C319, and also check Q304 if D305 is bad. Also be sure to check the flyback transformer.

Follow up: As I don't have a FBT tester, I decided to replace everything on my original list except D305 and Q304 (both tested good on DMM). I then installed a 100W light bulb in series with the anode of D305. On power-up, the bulb glowed at about 1/3 intensity for about 20 seconds and then went out. Now the bulb no longer lights, D305 has 180V on its cathode and 0V on its anode (tests good out of circuit), Q313 tests good out of circuit and Q304 is shorted. Does this confirm a bad FBT?

Check Q321 (IRF 640) and R363 22 ohm 5w (I think) this was probably the original cause but also replace as a precaution C368 22nF 2kv Z5U capacitor.

QUESTION NO. P17-6: Gateway EV900 monitor does not work and is missing resistor R573 and variable resistor VR501. Looks like burn marks on circuit board where they should be. Per other postings, R573 is 68K, 1/8w. What is the value of VR501? Could the monitor work without these?

VR501 is a 20K ohm pot. Also, in some OEM versions of this chassis, R573 = 67K; I don't know if this is significantly different from 68K. These components are all in the ABL circuit, and are necessary for proper function of the chassis. Check if D315 in the power supply secondary is open, or has bad solder; it can cause voltage problems that can ruin the flyback and other components. The flyback itself should also be checked, in case it is now damaged and overvoltages the ABL circuit. If so, it needs replacing. Ringing the fly may not reveal this damage. Gateway will probably be no help for replacement flybacks; if the fly is FEA658 or TF2-6V0-002-S0, try Cactus Technology, Nationwide, or Mag Innovision (the OEM manufacturer).

QUESTION NO. P1212-9: Packard Bell 1412sl monitor FCC H41CM14011 has normal display for a second then suddenly shrinks to one vertical line together with a click sound of a relay. Checked HOT and all the surrounding components in Horizontal side but seemed to be all good. Checked the Flyback (Sampo FEA306) and found the ferrite core detached, install to its original position but still no improvements. If the Flyback is confirmed faulty, where can I find this one?

Nationwide (www.neiparts.com) lists FEA306, and also suggests TFB4806 as a substitute. LJ Enterprises (www.ljent.com) is another possibility, since this chassis is a LiteOn. HR Diemen (www.hrdiemen.es) lists their HR46088, as replacing FEA306.

QUESTION NO. P13-9: AcerView 78ie monitor keeps blowing horizontal deflection Q314. I need the original part number, it was replaced earlier and I think my supplier gave me the wrong replacement part. I also need the value for R713, it was burned.

Q314 = BU2527AF, and R713 = 3.3K, 1 Watt. You might check the values on R732, R733, and VR701, as well as the function of IC602 = CNY17-2 (optocoupler) and IC702 = TL431, in case the 180 Volt rail is regulating too high. I'd also check drive cap C367 = 1 uF/100V, 105°C for bad ESR, and check RF3958 (1 ohm, 1 Watt, fusible), and ceramic cap C368.

QUESTION NO. P13-7: Sony 17SF2 monitor, HOT Q510 failed and had been replaced about one year ago by expensive Sanyo 2SC3998. Now Q510 dead once again as well as Q503, D505 and D596. I need characteristics of Zener diode D505 and also any comments about that HOT weakness.

D505 is shown as RD10ESB, which is a 10 Volt, 0.5 Watt zener, and is across the G & S leads of P-channel FET Q503. D596 is often 1SS119, which is only rated 30V, and commonly goes leaky. I'd try ECG519 or 1N4148, instead of 1SS119. Check for bad ESR/decreased value on C208, C503, and C525, and check film caps C540, C541, and C592. I'd also check if D501 or D504 have become leaky in reverse. Note, in this schematic, Q510 is an N-channel FET (FS10SM-18A); it is location Q507 that is the Sanyo HOT.

QUESTION NO. P125-4: Octek 1569SE monitor FCC DBL 1569E. Need values for C721, R712 and R717 in HOT circuit.

A CTX VL500, with the same FCC# DBL1569E, had C721 = 1 uF/50V, R712 = 33K ohm, and R717 = 12K ohm. I do not know if all the values will be identical in your Octek brand, but C721 and R712 are likely to be correct values, since their values are consistent in a number of CTX models (only the value for R717 varies). However, since these components are damaged when there is a bad flyback transformer, unless you replace the flyback as well, any replacement components will again be damaged from overvoltage.

QUESTION NO. P1218-1: Acer 79g monitor FCC JVP7279G. I need the values of Q313 and RF3929.

The schematic for JVP7279G shows Q313 = BU2520DX and RF3929 = 22 ohms, 3 Watt, fusible.

QUESTION NO. P1220-1: Compaq V90 model 631 monitor FCC BR8SM-994, Hitachi Tube. Has a black screen, no HV, static is OK, monitor acts like normal rgd green light, suspend and ST.by. Replaced shorted Hot- Q831, and pulse IC U505 (uncertain if replaced chip is ok, used). No other visible burnt components.

Besides the Q831, also check R866, FET Q563, and check the flyback transformer for any leakage (less than "infinite" resistance) from the HV anode to deck.

QUESTION NO. P1220-8: I need the value of R940 in a Compaq monitor CO1021T (710B chassis).

In the Daewoo 710B chassis, R940 = 100K ohms. This resistor can burn due to a bad flyback.

QUESTION NO. P1213-4: Belinea 105570 monitor keeps blowing the horizontal output transistor. Replacing transistor C5048 (Q301) with BU 2527AF makes the monitor work for few minutes (display is normal) before display blacks out.

When replacing any HOT, there are normally caps in and around the HOT that are open, leaky, or with bad ESR Also open resistors and/or diodes. Run the set at around 80 VAC and after 1 min or so turn power off and place finger on the HOT (the case not the heat sink). If it burns you, you have missed something.

QUESTION NO. P1217-1: Compaq V500 monitor, model pe1111 has intermittent video. I have diagnosed the problem to ic201 (number lsc508418b). I cannot find a vendor for this part.

This model is made by Samsung, basic chb5707l and the part number for ic201 is bh0900001a. It costs about $37.00 in Australia. When it goes, it will give intermittent video. To prove, use freeze spray.

QUESTION NO. P1218-3: TVM MD-14IV monitor flickers all the time it from big display to small display.

Check for cold solder joints, and bad solder connections in general. If there is a lot of flux on the board then it is a good indication of a bad solder job.

QUESTION NO. P1217-2: Princeton ultra 90 monitor dead. Replaced shorted HOT. No b+ voltage. No obvious resistor shorts. fuses ok.

Princeton monitors are made by several OEM manufacturers, like KDS, Sampo, ADI, etc., so an FCC or chassis code number is needed to identify the OEM. Some of these 19" Princetons are made by ADI, and are similar to ADI's PD-959 model. See if your unit has an FCC or chassis number that indicates the PD-959 model. If yes, when the HOT Q831 shorts, it generally opens B+ resistor R866 = 2.2 ohms as well, removing B+ from the HOT. The FET Q563 should also be checked, as it can be damaged, too. Often, the cause of shorting Q831 is a bad flyback transformer, which must be replaced, or the HOT will die again. The flyback may be either model LZ250A000P or FEA662.

QUESTION NO. P1214-4: Acer 7177is monitor is missing +12v. The voltage measured at P310 for the 12v is .470v. IC304 pin 9 reads .470v. I need to know which circuit provides the 12V.

The +12V comes from +12V regulator IC303. IC303 is powered from the +16V supply, via pass transistor Q701. Q701 must be energized by Q702, in order to pass voltage. Q702 can be turned off by a "suspend" signal from IC701, or if the +24V supply is missing.

QUESTION NO. P1213-5: Mag monitor FCC IAWU8010 has Q301 shorted, R349 open, R350+351 open. I cannot identify R349 other than the first band. The bridge seams ok. No other shorts on the input from AC noted. The TM302 thermistor in the degauss circuit has a part blown off but does not measure shorted. What are the values of these components and what other things do I need to check? ie. typical resistance on the output of Q301.

The schematic for this Mag shows Q301 as Mosfet FS7SM-16A, rated 800 Volts, 7 Amps, 150 Watts; a STW8NB80, IRFPE50, or NTE2377 might substitute. R350 & R351 = 0.22 ohm,1 Watt; R349 = 1K, 1/4W. Assuming that you meant TH302, it is N15SP005 (a 5 ohm, 6 Amp inrush current limiter), equivalent to a Thermometrics CL-40 device. With these parts damaged, I would also check/replace ZD301 (15V zener) and IC301 = UC3842AN, check fuse F301, and ring SMPS transformer T301.

QUESTION NO. P1212-2: AcerView 79g monitor. I need the value of RF3929 which was burned. I checked Q313(BU2520DX) and all the parts in this area. I put (15 Ohm) and same problem.

RF3929 = 22 ohms, 3 Watts, fusible. Possible reasons for its burning might include excess voltage on the 180V rail; shorts or leakiness in components Q304, D305, C318, C319; and especially a bad flyback T301. Check the 2KV-rated caps C317, C384, C385, C386, as well, although probably these would not directly cause the resistor to burn.

QUESTION NO. P1212-5: Mitsubishi Diamond View (1772E) monitor FCC JVP7276E. I need the value of r241 (totally blackend) and the reason for its demise.

R241 = 10K ohms. The usual cause is a bad C327 = 220pF/2KV. This fault can also damage HOT Q302, Q301, IC201 = TDA4858, ZD210 = 5.1V zener, R326 = 3.9K, R328 = 4.7K, R329 = 10K, J013 (3 Amp microfuse), and possibly C326 & C331, so also check all of these.

QUESTION NO. P1212-7: Dell 1728-LS monitor, built by Samsung. The raster, color balance, purity, convergence and screen display are all normal. The brightness and contrast controls are operative, but the maximum brightness is very low.

See if the screen voltage or the heater voltage is low. If the heater voltage is bad, check the solder, and the value, on components going to the heater, including SMPS transformer T601, D617, R620, C644, J311, J309, CN603, CN105, R165, etc. Also check the ESR, as well as value, on C644. If these are all OK, try checking the CRT emissions.

QUESTION NO. P1210-7: CTX VL950 monitor had a shorted Horiz Output trans which prevented unit from powering up. Replaced transistor and now have led & degaussing action but no High Voltage. Checked around for other part failures but no luck.

Raw B+ (about 200V) feeds through the FBT primary to Q403, and then its voltage is regulated past the emitter of Q403, by a coil which is chopped by FET Q338. See if the coil and Q338 are good, and if the PWM IC, IC303, is providing Q338 with good drive pulses. If there is no drive, try troubleshooting the UC3843 and surrounding circuitry, including the HV trimpot feeding back to IC303 from a flyback winding. Also check for good drive to Q403, from the H/V sync processor IC, which sometimes goes bad.

QUESTION NO. P1121-8: Eizo T662 monitor, screen settings are not stored . Always "default" settings at power on.

I know this problem from the T562 (17") model, the chassis of T662 (20") should be the same. Replace the eprom (IC 802), type BR93L66R. It is a SMD component (Eizo part #08N27578T1) on the video-panel (back of the monitor).

QUESTION NO. P1210-6: KDS VS-7i monitor is dead, no leds or noise, no apparent burnt components, fuse not blown.

Check for broken solder on the SMPS transformer, and on the flyback.

QUESTION NO. P1119-4: Looking for correct pinout to a Dell D1028LR monitor with Philips CM6800 Chassis (FCCA3KM066). The cable is cut at the VGA connector, pinout for the VGA is no problem, but I need the pinout for the internal connector.

www.epanorama.net/links/repair.html.

QUESTION NO. P117-7: I need the pinout of the signal cable of a Dell M990 monitor FCC A3KM085 (Philips)? The cable is cut at the monitor side. (I know the connector-pinout, need the pinout of the internal connector.)

www.epanorama.net/links/repair.html

QUESTION NO. P111-1: Client was burgled, the intruders stole the PC's but cut the data cables and left the Gateway EV700 monitors which according to the FCC search are made by LG. PN 7000920, 700-069ev, FC BEJCS780. We have been unable to locate new data cables. We have been able to sort out there/green etc but we are left with several cables and the permuations will take hours to go through. Does anyone have a source for the cables or a pinout/color diagram for this model?

www.epanorama.net/links/repair.html

QUESTION NO. P1129-3: Samsung CGK5507L SyncMaster 500s monitor has no horizontal size or pincushion control. Buttons on front panel indicate functionality, but have no effect on horizontal size adjustment or side-pincushion and trapezoid adjustment. Q409 and VR401 were replaced.

Try checking Q407, D405, D404, D412, for reverse leakiness or short, and L402 for burnt/shorted turns or rings badly.

QUESTION NO. P1116-3: Daewoo 710b monitor . I need the values and source of Q577 and Q935.

In my Daewoo 710B service manual, Q577 is 2SK2799, a 350 Volt, 10 Amp, 50 Watt, N-channel FET. A possible substitute might be IRF740A, with insulator. This service manual shows no Q935, either in the schematic or in the parts list; perhaps Q935 was added in a later modification.

QUESTION NO. P118-10: Daewoo or Daytek DT-1728 D monitor, OC-17DB06. I need the values of R918 and R919 which are burnt out and why burnt out.

R918 10k and R919 is 1.2k. I have never had this problem before, but check Q901, IC901 and Q906. Also check to see if any of the diodes in the power supply circuit are shorted, mainly D901.

QUESTION NO. P1114-4:L Viewsonic 1769gs-2 monitor FCC gss17005 has no hi-voltage. Fbt, hot, etc seem ok. Replaced lm-2931 & 74hc00 on the aux. board. All ps voltages ok

If the HV builds and collapses, and everything else is ok, then you may have a shorted transistor on the CRT socket board. Try desoldering the RGB cathodes at the CRT socket and see if the HV builds and holds.

QUESTION NO. P1023-2: Gateway EV900-7000595 monitor. I need the value of R537 which is burned. What could have caused this?

Did you mean R537 or R573? R573 is 68K, 1/8w.

QUESTION NO. P1029-9: Apple 1710 A/V monitor would tear horizontally after warmed up. By blowing air across rear of unit from external cooling fan, problem would go away. Before I was able to track down faulty component unit went dead. No Power LED no HV.

The problem is on the CRT socket board.

QUESTION NO. P115-1: Sun/Sony GDM-20E20 monitor when turned on, the power LED turns solid green for a few seconds and then goes off ,and immediately after that the other LED (standby/power saving) turns amber and blinks. This happens irrespective of whether the vga cable is connected or not.

Start with Q507 (IRF9630), Q508 (C3997), PS501 (pico fuse, open). Sometimes IC420 (CXA1907S) causes problems but they are usually related to G2, Dim picture etc. While you're in there, better check soldering around the FBT and also filament voltage supply caps C677 and C683.

QUESTION NO. P1114-8: Compaq S500 model PE1112 monitor chassis cmc-518x/522x clicks the relay when power on and the power led blinks. Found R554 fried, what is the value and what could be the fault?

R554 is 15k , 10% , 0.5watt.

QUESTION NO. P1114-7: Hyundai 7870A monitor takes about 5 min. for the screen to light up. The screen is dark the HV is Ok and it gets lighter and lighter until the luminance is almost ok.

Sound like a Samsung CRT problem. If your CRT is M41KUK36X07 then this is most likely your problem.

QUESTION NO. P1017-4: EIZO-monitor F56 with high-voltage breaking down for 1 - 2 seconds than is ok for 5 seconds, then the same problem again. When high-voltage is breaking down, a "strange component" (it's not a resistor, but it looks like a 0.25 W-resistor in a transparent tube, color-rings green-red-white, named SG702) shows sparkling.

"Strange component" is a spark-gap (SG702). Usually bad news when one of these light up. Tube is gassy and anode voltage (24 to 27kV) is leaking into one of the connection on the tube neck protected by the SG.

QUESTION NO. P1115-5: Acerview 54e monitor shows a green tint.

First try resetting to factory settings, by pushing both the Select+ and Adjust- buttons simultaneously. If there is no improvement, try checking the video board for bad solder/connections, bad electrolytics, or leaky bias transistors.

QUESTION NO. P1114-5: Panasonic S50i TX-T5F73 monitor is dead. On main power supply board, R803 SCK162 is broken.

SCK162 is an inrush-current limiter, rated for 2 Amps, and initial resistance of 16 ohms at 25°C. A Keystone Thermometrics' CL170 device should substitute; Mouser Electronics (www.mouser.com) lists CL170. This monitor may have taken a surge on the AC power line, or had a short in the primary. I would check main cap C820, bridge diodes D801-D804, line filter L801/L802, fuses F801, F802, F804, F805, and FET Q820. If Q820 had shorted, check components off its gate, including IC820, and ring T801.

QUESTION NO. P117-10: Optiquest V73 VCDTS21433 monitor is dead, the led stays amber. All the caps are ok with ESR.

Check Q550, Q881, T823, and IC841.

QUESTION NO. P116-4: CTX vl700 monitor is dead. Q313 (HOT) shorted, replaced by ecg2365 & Q306 (mosfet J306) short & replaced. Dead again, both are shorted.

Besides replacing Q313 and Q306, CTX advises upgrading C340 to 47 uF/250V. Also check ZD303 and R362. If your VL700 (there are multiple versions) has R124 = 82K in the power supply, check that its value is correct, in case this has caused an overvoltage problem. If this is no help, I would suspect a defective flyback, FEA667.

QUESTION NO. P1031-4: Sony CPD200GS monitor. Is it possible to reset when the firmware appears to be corrupted?

To re-set adjustments to factory settings, hold the Reset button (second from left) in for over two seconds. A self-test can also be done, by powering on with the video cable disconnected, and pushing the right-arrow button for over two seconds. Four color bars should then appear, to indicate the self-test has been passed. To change the internal programming, you must use Sony DAS service software, which is run on a PC with an interface consisting of adaptor cable, Sony p/n#1-690-391-21; Interface Unit, Sony p/n# A-1500-819-A; and connector attachment, Sony p/n# 3-702-691-01.

QUESTION NO. P115-2: Digital FSR871CV monitor, need part no for diode v805. Already replaced R849 and R869.

V805 is a Philips BY584. This is a special high-voltage diode (1.8KV, 85mA); do not use a substitute. A good one will probably read open-circuit on a DMM diode test, since its forward voltage will be about 3V even with just a 1 mA test current. MCM Electronics (www.i-mcm.com) and Nationwide (www.neiparts.com) are listing BY584.

QUESTION NO. P115-7: Acer 7176ie monitor has problem with pincushion. Can align either side perfectly but the screen curves on opposite side. I replaced Q312, Q313 but this has not made any effect.

There may be a problem with the Pincushion Balance (PB) adjustment. Try adjusting this, in factory mode. Power up while holding in the P button, and release the button after the LED flashes. Enter the OSD, go to the PB page, and try this adjustment.

That function does not even out both sides of the full view. If I keep the P button pressed it will not matter, that will just start the OSD with no different menus. If I adjust the pincushion to the left the right side gets curved, if I adjust it to the other side the same thing will happen. When I start the computer it looks like a D, if I adjust it it goes to the other side as a opposite D.

QUESTION NO. P115-10: CTX VL700 monitor. I need to identify Q306, J449, I believe this to be 2SJ449 a p-channel mosfet. Is this correct and is there an alternate component similar that can be used?

Yes, that is 2SJ449. An alternative P-FET to 2SJ449, would be 2SJ307.

QUESTION NO. P104-8: Sony CPD 200-GS monitor. I changed Q507, Q520, IC605 (bad), verified all the components near F/B (ok). What may can cause Q507 to burn up, when I power up the monitor? Q507 shorts right away upon powering the monitor.

Is there excess voltage on the SMPS secondaries, due to bad regulation? If so, check the value of R628 and R630, off the 180V rail, as well as IC604 and opto IC603. If the 180V is close, then Q520 should drop the B+ voltage for the collector of Q507 down to about 74.6 VDC. If this voltage is too high, check Q520, D516, C575, and the drive circuitry for Q520. In the drive for Q507 itself, try checking Schottky D502, the values of R517, R518, R522, the H. drive cap C508, Q511, and T504. Also check tuning cap for the HOT, C518, (also C521, C522, C579), the damper diode D506, and the solder connections for the horizontal yoke.

QUESTION NO. P103-7: Compaq Qvision 172 monitor, I cannot adjust the horizontal and EW amplifier. The image on the screen is not tiled (the vertical module appears to be good).

If you meant, that the horizontal width was too small, and the horizontal width and E/W would not adjust, try checking the small SMD transistor T60, usually marked "3F". This is a PNP transistor, equivalent to BC857B.

QUESTION NO. P1016-1: NEC Multisync 70 monitor (model PN 7701), R323 is slightly burnt and I want to confirm its value.

R 323 is 1K Brown/Black /Red.

QUESTION NO. P1030-6: Samtron 70E BASIC CHB7227L monitor FCC A3LCHB770, the raster width is more than screen width, can be adjusted by front panel digital control but minimum is more than screen. Originally EHT Xmer, Q506(A733 transistor) & Q504 (IRF730 mosfet) were bad replaced. Present pb is above mentioned IC501(TL494) POT & resistances are OK & if POT of width ctrl is varied there is no variation (at PIN 3 of TL494 the voltage is changing but I think it should stabalize to 1.7(neg. feedback)).

For abnormal horizontal size, the Samsung CHB7227L Service Manual says to check the output duty cycle at IC401, Pin 24. If output duty cycle does not vary with different B+ offset DAC values, check/replace uProc. IC201, and check components off of IC201, Pins 12 & 16, and IC201, Pin 23. If duty cycle does vary, then check for a good waveform at T402, Pin 10, on a scope. If it is good, check components around D432; if bad, check/replace T402. Beyond the manual's suggestions, also check Q433, L431, C431, C432, C433, & see if D431 was leaky. Also, IC401 itself is a known high-failure component.

QUESTION NO. P102-2: Samsung SyncMaster 753DF Dynaflat monitor, cannot adjust control panel switch. I replaced IC201 (DM024).

For User Control Failure, the Syncmaster 753DF Service Manual says to see if the DC voltage changes at Pin 36 of IC201 when SW201 through SW204 are pushed, and if no change, to check the button. If the voltage does change, it says to check IC201.

QUESTION NO. P1018-2: Samsung SyncMaster 6C CSG 9511 monitor. I need value of burnt Q504.

My schematic shows Q504 as a 2N4403, in the circuitry for T504.

QUESTION NO. P1016-10: NEC Multisync70 P/N PN7701 monitor is dead. The fuse is open; th101 broke; q101 is burnt w/o markings, also zd101 also burnt. I need their values.

F101 = 3.15 Amp fuse, Q101 = Mosfet 2SK2645 (600 Volt, 9 Amp, 50 Watt, N-channel), and ZD101 = 18V Zener. Since ZD101 and Q101 burned, also replace IC101 (UC3842). TH101 is an inrush-current limiter device, rated at 5 ohms with no load, and 4 Amps max.; a Thermometrics type CL-150 (Mouser cat.# 527-CL150, or Digikey cat.# KC015L-ND) could substitute for those specs.

QUESTION NO. P1015-1: AST Vision 7N monitor. I need the values of R915 and R916.

If this AST 7N model is similar to KDS models KD1710 & KD1711, made by Korea Data Systems, then the values in the KDS schematic read as R915 = 180K and R916 = 100K.

QUESTION NO. P927-2: Dell d1025he monitor FCC iey447s. I replaced the hot as it was shorted. Now on turn on, there are power supply voltages but nothing on the collector of the hot. I am getting the correct pulses on the base of it but still no H.T.

See if R411 has gone open-circuit. If so, before powering up, also check D404 and T404.

QUESTION NO. P1023-2; Dell D2026T-HS monitor is very dark (only can shows the OSD). We found a low G2 voltage, the G2 control transistor is ok. Is there a protection control circuit that shuts it down?

Assuming that your Dell's FCC number shows that it is a Sony GDM20E03 chassis, the probable cause is a defective IC, CXA1907S, on the CRT board, Sony part# 8-752-071-56. If the output voltage from pin 22 of the CXA1907S is too low, going to IC407, this will cause low G2 voltage. To remove the old IC without lifting PC traces, it is best to cut off each pin, and remove the pins one at a time.

QUESTION NO. P1015-2: Philips 4CM4770 monitor intermittently out of sync. In the deflection circuit found TDA4850 (and TDA4861), TDA2595, HEF4528BP and a 74HCT86N.

Hor. or Vert sync? If hor, check components around the Hor Osc of TDA4850 and check components around Vert Osc if Vert sync problem. If there is a pot for adjusting the Hor hold, then adjusting that might help since it might not be optimum.

QUESTION NO. P1016-4: Mag DX1795 monitor. The HOT was blown and the replacement blew instantly. Flyback rings good, T501 and FET Q506 OK. A casual check of nearby semiconductors revealed nothing, no visual clues.

Although the flyback rings good, the capacitor inside might be shorted. There is a 3nF capacitor in the flyback. Firstly with a multimeter connectng one end of the probe to the anode cap and another to the ground/feedback pin of the flyback. If you do not know which is the pin then try all. It should all be open. If low resistance, then you have a bad cap. Refurbish the FBT or get a new one.

QUESTION NO. P1019-3: Acer 1555 monitor came in with an S/C line output transistor, type BU2508DX. I fitted a BU2508DF as the nearest equivalent. It now has a small picture, width about 50% of normal is the best it can do , but perfect geometry which is adjustable. The B+ PWM is only delivering 60v to the Line Stage (should be around 90-100v). The drive to the PWM FET Q317 is correct, but I replaced the TDA4858 anyway. L304 and D317 replaced too, to no effect. I cannot decide whether the line stage is drawing too much current (Flyback tranny failure?), or some other component in the output stage is causing the fault. C335 is an upgraded 3kv cap ex-factory.

Ring the yoke or swap a tube/yoke assembly to confirm that it is not the yoke problem. Narrow horizontal width can be caused by shorted yoke. Since all the geometry control works fine, I cannot think of anything else to do except the above.

QUESTION NO. P1019-9: Dell 828Fi monitor. During bootup sequence, it seems to loose horizontal sync and controls have no effect. I suspect TDA9109 might becoming progressively faulty, but I would like confirmation.

TDA9109 is a common failure in this chassis, and it can give a variety of symptoms, such as jitter, bad linearity, loss of sync, loss of user settings, etc. Try some freeze mist on the IC, sometimes that helps diagnose it. If this IC is replaced, be sure to use the exact same version of TDA9109, as was originally installed; TDA9109 and TDA9109/S are different chips.

QUESTION NO. P926-3: Daewoo 710B Monitor with R939 burning up. I need the value and why it has gone o/c.

R939 = 100K ohms. When R939 burns (and/or R935, R940, R947), a faulty flyback transformer is the usual cause, and needs replacing.

QUESTION NO. P1017-2: Sony gdm20e01 (Radius 0461) FCC ak8gdm20e01 monitor. I need the value of R868.

The value of R868 varies, in different versions of the Sony GDM20E01. If R851 = 2.2K, then R868 is also 2.2K ohm. Some chassis have R851 = 5.6K, and there R868 = 1K.

QUESTION NO. P1017-7: Compaq V90 model 631 monitor. Replaced the HOT(BU2520DF) and FET (k1006) which was shorted and burnt 2.2ohm resistor. It started to work, now I hear a loud "tick" sound from FBT or nearby intermittently. At the same time the picture shrink or move a bit and go back to normal. I tested it for 3 hours, same problem, I also did a cold start and still same problem.

The flyback (Sampo FEA662) is probably faulty; it is a common failure in this chassis, and a faulty FBT can cause those components mentioned, to fail. Also, check the components off pin# 8 of the FBT, as well, for possible damage.

QUESTION NO. P1010-9: ctc-146L monitor is dead. Changed HOT, fuse and R106u 4.9ohms. cr118 is ok.

Locate broken ground connections at the rail that goes around system control IC's U3100 and U3300. The rail is used as a ground jumper to connect the ground to the control buttons, solder the rail ground connections. For more info trywww.videotech.org/rca.htm.

QUESTION NO. P1015-10: Acerview 7154ei monitor, replaced burned output transistor q310 and d312, still no power and the power lamp is still blinking. I checked regulator q602 in the power supply, it is okay. I checked switching transformer in the power supply and found 80 volts in the primary and secondary no voltage, also no 5 volts in the regulator and no 12 volts.

Replace disk capacitor C335, and check R214; if R214 is bad, also suspect IC201 is bad. Check C319, D316, D317, FET Q317, and coil L304.

QUESTION NO. P1015-9: Need part number for Q901 in power supply of AOC 4V monitor.

Q901 is IRFBC40. This should be available almost everywhere.

QUESTION NO. P918-10: Daytek DT-1536D monitor is dead. D813 failed short circuit. IC801, R820, R905 burnt. What are values for these components and did failure of D813 cause problem?

D813=Z6.2M,ECG 137A, IC801=STK73907 (12 pin Sanken brand sw reg IC), R820=22K ohm,1/4 w, R905=does not exist, R805=33K ohm,1 w, R804=33K ohm,1 w. Check Q807=2SC3230,Q802=2SA940,D814=1N4148, solder T403=pin 1 of flyback,R445,and R444.

QUESTION NO. P109-8: Gateway ev700 monitor, picture is red, on screen menu prompt has all colors. Checked red, green and blue crt drive transistors ok. Green control on crt board has no function.

Found problem with serial port on computer, all colors there when wire was wiggled, repaired solder connections on card.

QUESTION NO. P1011-3: Sampo Alpha Scan 950 monitor, will not light up, just ticks. Can this be the high voltage power supply? If so where can I find this part, I've searched everywhere?

If your everywhere includes the HOT, damper diode, fast rectifier diodes, diodes around the deflection circuit, no bulging or shorted capacitors, then I suggest that you check the flyback. I have refurbished many Sampo flybacks before, they tend to have an open capacitor or shorted coil. To confirm, ring the flyback. To check the capacitor in the flyback, connect a capacitance meter with 20nF range and measure the internal flyback capacitor from the anode cap to the ground/ feedback pin on the flyback. You should get about 1.5 to 3nF. Much more or much less, you have a problem.

QUESTION NO. P1012-3: NEC jc 200 2vma-1 monitor. I replaced the horizontal transistor HPA 150. It works well with the horizontal york plug off the motherboard. The minute I put it back it, blows the transistor. Checked for any leaks into the chassis, it seems to be fine.

On NEC's, when the HOT blows, the B+ regulator FET generally also is damaged, and if both are not replaced at the same time, the damaged FET will blow the new HOT, from excess B+. There's a couple board versions in JC2002VMA-1; usually the regulator FET is Q5P0 = 2SK758, but may be Q5G6. Also check H. drive cap, C541 = 100 uF/35V. Be sure your HPA150 has an internal damper, despite the presence of D561 & D562.

QUESTION NO. P1012-8: KDS vs-7 monitor FCC evokd-1730. The power supply keeps cycling power on and off or power led flashes on and off and power supply makes a clicking noise. I replaced blown hot, it tried to turn on for a second but still cycles power checked hot and still good.

If any of R901, R902, R903, R904 are burnt, the flyback is bad and must be replaced. Also check IC401, if R904 is bad. Check D402, D404, D405, D407, D409, D410, D411, D412 for leakiness; C438, C468 (under FBT), C816; Q406, Q407, Q408, Q415, Q416.

I am not familiar with this model but very familiar with this symptom. Firstly ring the flyback. If the primary rings well, check if there is about 3nF from the anode cap to the ground/ feedback pin on the flyback. If less than 1.5nF, the HV capacitor in the flyback is opened. Check for short in the capacitor as well since shorted capacitor in the flyback tend to blow up components like HOT, B+ boost transistor, diode around the deflection circuit and cause the power to cycle.

QUESTION NO. P1012-10: Vicom vm615-2 monitor, replaced d14 and fet w931/p4na80 (replaced with irfbc3) shorted. Worked for awhile then fet shorted. Checked all resistors and diodes and replaced ic tda 4605 in the power supply.

The (ST)P4NA80 is an 800 Volt, 4 Amp Mosfet, and your IRFBC replacement was only rated for 600 Volts. Try a FET of the original voltage. Mouser Electronics (www.mouser.com) lists STP4NA80 and STP4NB80 (cat. no.'s 511-STP4NA80 and 511-STP4NB80), both rated 800V. These have TO220AB cases (not self-insulated TO220FI cases).

QUESTION NO. P1011-6: Micron 700FGx monitor HV9 chassis. I need a cross reference for Q881 (a TO-220 (plastic tab) marked J306 7H3.

J306 is a 250 Volt P-channel Mosfet; the full number is 2SJ306. 2SJ306 should be available from suppliers like LJ Enterprises, B&D Enterprises, MCM Electronics, Nationwide, etc. Possible substitutes include P-FET's 2SJ307, 2SJ449, or IRFI9634G. Although I can't recommend this, I believe that in the HV9 chassis, Q881 switches a 170V rail, so, in a pinch, it may be possible to "squeak by", using a 200 Volt P-FET, such as IRFI9630G, or an IRF9630 with insulation hardware.

QUESTION NO. P1010-6: Acerview 76e monitor. Replaced shorted c237 and burned r239 and r241, now the led comes on then goes out.

Assuming you meant C327 (not C237) & R329 (not R239), then besides the parts you replaced, check the microfuses at J013 (3 Amp), F701, F702, F703, F704, FR101; as well as C304, D308, L304, ZD210 = 5.1V zener, IC201, Q301 = BSS89, Q302, and Q316.

QUESTION NO. P109-1: Samsung 400b monitor. I need a source or sub for switch header "KA2S0880". I believe that it is the TDA9109.

The KA2S0880 is a Power IC (5-pin TO3P case), made by Samsung or Fairchild; it will be mounted on a heatsink. It is not the same as a TDA9109. There is no substitute for KA2S0880. In the US, try getting KA2S0880 from LJ Enterprises (www.ljent.com), or Nationwide (www.neiparts.com).

QUESTION NO. P103-10: Dell UltraScan 17TX monitor FCC AK8GDM17SE2T came in with tilted picture and blurry screen. Adjusted the screen and focus controls and got focus, however, the words and letters are in the 3 primary colors, red, green, and blue. Cannot seem to get the (Purity or Convergence?) adjustment in. The screen tilt was temporarily fixed by disconnecting a wire on the Yoke board. Screen came in with all yoke and crt adjustments loosened.

You are going to need a service manual, to correctly adjust the purity. Try to get the manual for a Sony GDM-17SE2T, which should be similar, from a Sony distributor.

QUESTION NO. P103-8: CTX 1451c monitor when shutting off it decays too slow causing a burn spot on the phospher in the middle of the screen.

Try checking Q408 (BF423) for leakiness or short.

QUESTION NO. P102-8: Compaq V75-624T monitor, the power led becomes green and after a few seconds dies. HOT is OK, output vert. transistor is OK. Is in PWSP the trouble?

Could have a faulty flyback transformer.

QUESTION NO. P102-1: Samsung Sync Master 550s monitor there is power but no display (no static sparkling). I checked & replaced FBT, CRT Display Unit and Video PCB Board.

Be sure that there is 6VDC in the filament hot on crt and move the screen boton on the flyback. Check if 70 or 80 VDC exists on the cathodes of the color transistors. Check the circuit of ABL it can has a resistor open.

QUESTION NO. P925-1: Compaq V70, 629 monitor, FCC BR8SM-769(ADI). Replaced shorted HOT Q813 (2SC4542), transistor failed almost immediately. B+ OK. Horizontal drive pulse OK.

First ring the flyback. If the primary rings well, check the HV capacitor by connecting a 20nF range capacitance meter between the anode cap and grounding/ feedback pin on the FBT. The meter should read 1.5 to 3nF generally. If lower or shorted, change the FBT.

QUESTION NO. P925-4: Dell D1728D-LS monitor, FCC A3LCMG737 will not power up,.no response. Switching power supply appears OK except no 12VDC at one point on board.

Check if R508 has gone open-circuit. Depending on the A3LCMG737 board version, it can be either a small-value (1.8, 3.3, etc, ohm) fusible resistor, or a 1 Amp microfuse, on the 195V supply. If it is bad, also check if HOT Q502 has shorted, as well.

QUESTION NO. P828-10: Dell D2026T-HS Ultrascan 20TX Sony vertical is very unstable, poor pincushion. The front controls will not adjust the vertical width or position. I am suspecting the circuit around ic 502. I replaced the vert ic TDA 8172, and all electrolytic caps around it with no effect.

I am more suspicious of the IC007 (Sony part# 8-752-076-34), on the D board, than of IC502, for this type of problem; it's a known failure component.

QUESTION NO. P828-9: Sony CPD-420GS monitor missing Q901 and Q902. Need part #'s for these and any common failures.

In three similar Sony models (GDM-400PS, GDM-500PS, CPD-520GS), the Q901 = 2SC1623 and Q902 = 2SA1037K, so probably they are the same types in the CPD-420GS, as well.

Q901 is a IRFI9634G (Sony # 8-729-043-63) Q902 is FS7KM-18A (Sony # 8-729-045-22).

QUESTION NO. P827-2: Compaq 461 monitor FCC IDBR8SM-5514N. I need the part number for HOT Q809. Also can the damper diode CTPG2F be substituted with FMGG26?

Q809 is 2sc4747.

QUESTION NO. P925-9: Water damage from roof leak on a KDS monitor FCC EVOKD-1730. I need the value of R901, 902, and 904. All have burned badly. I have not found other parts in this area of the circuit that are defective. What may have caused these resistors to burn up? All are 1/10 or 1/8 watt resistors.

R901 = 27K, R902 = 12K, R904 = 12K; use 1/4 Watt. These resistors will burn when the ABL section of the flyback, KFS61411A, is defective; replacement FBT's are availablefrom KDS. Since R904 has burned, IC401 may also have been damaged.

QUESTION NO. P924-8: Digital PCXAV-WZ monitor. I need a source for flyback CP334P05301. It seems to be a Mitsubishi flyback very rare to found.

Nationwide (www.neiparts.com) lists flyback CP334P05301, but it is an expensive one.

QUESTION NO. P918-2: Samsung CGC5607L(D)(T) monitor, the label is in Korea, the only info that makes sense to me is (maybe) the ModelSyncMaster 500p(T) was initially dead. Replaced D406 (part no CTPG2F) with a FMGG26 which was shorted. Unit powered up for about 2 minutes, then the image started to shake and went dead again. Once again D406 was shorted. I found out that the original diode was rated at 1500V 10A and my replacement was only a 600V 4A ultra-fast diode.I then replaced the diode with a Philips BY359-1500 but when I powered up the unit it still remained dead except for a low pitched ticking sound coming from somewhere around the horizontal deflection circuit. Did my earlier replacement damage anything else or worsen the problem?

Unless you forgot to use insulation hardware on the tab of that BY359, it does seem likely that the shorting of the FMGG26 has damaged additional components. First check if Q407 has now also shorted. If that is OK, see if any components along the B+ circuit for Q407 were damaged by the overload from the shorted FMGG26. Start with boost FET Q412 and ultrafast rectifier D411; if these are OK, then start checking components on the circuit providing the 50 Volt supply for Q412.

QUESTION NO. P918-6: Gateway monitor EV900 made by Mag is dead, no high voltage. Power supply seems ok but no b+ to collector of horizontal out transistor. There is 200v on drain of Q107 which supplies the b+. There is no out put from IC101 NE555 which supplies gate signal to turn Q107 on.

The common cause of no HV, when the power LED is lit, is bad solder on all the leads of L501, near the flyback. Resolder all the leads, regardless of appearance.

QUESTION NO. P919-7: Dell D1025TM monitor (Sony chassis) with bad HOT, damper diode, and fet w/protect zener. I can locate the original HOT, and fet w/protect zener but cannot find the damper diode. The only numbers on the diode are DLA 8-J. Sony does not support this monitor and Dell has been unresponsive.

Toshiba makes a family of rectifiers with the marking "DLA" and a date-code. Although it is not the damper, I suspect you are referring to D516, a Toshiba 3DL41A, a 3 Amp, 200 Volt, superfast rectifier. The original is Sony part# 8-719-051-97; similar rectifiers include NTE/ECG 588 or Rectron's SF34.

QUESTION NO. P921-4: Micron 700FGx monitor. Looking for correct value & voltage on the ceramic capacitor C556, in chassis #HV9.

In the Panasonic 17HV9 chassis, C556 is 470 pF, 2KV.

QUESTION NO. P913-9: Data General CM1414t monitor has a Panasonic picture tube. It is too bright and it has retrace lines. I checked the back board, it checks ok.

Do you have brightness control? What is the voltage at G1? Normally if the screen pot on the flyback is not tampered with, excessive brightness could be caused by shorted or open components (open resistor is quite common) along the brightness circuit. G1 should be a -ve voltage and becomes increasingly positive when brightness is increased. If you do not have any brightness control, it is almost definite that the brightness circuit is gone. The negative voltage for the brightness circuit is almost exclusively generated by the flyback. Trace back from the rectifier diode connected to one of the flyback pin and replace all faulty components.

QUESTION NO. P910-10: Dell D825tm (UltraScan 800 series) monitor, very dim picture. C653 which filters the line going to the filaments is missing.

Try 2200uF/16V for C653. This is a common value for filter cap of filament supply. Filament should be around 6.3V generally.

QUESTION NO. P921-1: NEC MultiSync P750 (JC-1744UMA-1) monitor, I need to find a replacement for Q591. It is shorted and causing the power supply to cycle. The only numbers on the device are "J306" and "7G2" Of course no help from NEC. Cannot find any info on their website (used to have parts lists online).

I believe the number you need is 2sj306 which is a mos p fet 250v, 3a, 25w. A 2sj307 will substitute ok.

QUESTION NO. P824-7: Mitsubishi DiamondView 2107 monitor, vertical sides "tremble" intermittently. Problem is not due to computer configuration or environmental EMI influences.

Check for cracked solder joints around r345, t304. You may have to remove white glue to see joints properly.

QUESTION NO. P911-3: NEC JC 1531-vmr model 4fg monitor has drifting horizontal sync. Adjusting horizontal hold pots vr501 & 502 will fix sync for a short time then it fails again. Replaced LA7850 and assoc caps- no change.

Check IC 74xx86xx somewhere on the main board close to the cable coming from the crt bd. This ic takes the horizontal and vertical signals from the computer and feeds to the required ccts. It can be influential in resolution changes.

QUESTION NO. P917-4: Dell D1028LR monitor comes on, but goes off when computer is restarted and refuses to power up again. No green light, yellow light flickers sometimes.

Replace component 3110. (Resistor - 220K, 1WJ)

QUESTION NO. P914-4: Compaq P70 model 622 monitor deflection is distorted at bottom half, space between lines becomes much wider on a band of approx 1 centimeter, and also the picture cannot be adjusted to cover the last centimeter of the bottom of screen. (Even if trying to adjust picture height to max). Have another one with the same problem, but at the top of screen.

Check the vertical IC TDA8351, check whether sufficient voltage is being provided to pins 3 and 6, and check for cold solder joints around the vertical section.

QUESTION NO. P914-5: Compaq V70 monitor FCC A3LCGL777, the video is squashed into the center leaving a vertical bar about 1 inch in width. I checked for dry joints / obviously burned components, and have found nothing.

Check if the deflection HOT (BUH1015, MJW16212, or similar) is breaking down under load, or is arcing to its heatsink. Also check the value on the B+ resistor (2.2 ohm), and whether the B+ regulator FET (IRF740 or similar) is being driven by the PWM driver IC (KA3883, or UC3843A, or similar).

QUESTION NO. P914-7: Sun/Sony GDM20D10 monitor, image is moved to the right of 5 centimeters. It is not possible to regulate with the remote control.

Check IC103 (Analog Devices' DAC8840FS), Sony part# 8-759-041-45.

QUESTION NO. P820-1: Acerview 76C monitor, when one side is concave the other is convex, the front panel adjustment as a full range but the picture will not go straight on both sides at the same time. Replaced IC 201 (TDA4858), Q303 Q310 (IRF 630) Q308, Q307.

Check all power supply based on the schematics at http//rv6llh.rsuh.ru/acer/76c-sch0.pdf. Check components around IC202 TDA8351 as failure of this IC is quite common.

QUESTION NO. P913-10: Royal Monitor FCC HSUTRLX-754 functions fine other than the Horizontal Width adjustment no longer functions and the picture stretches beyond the tube. There does not seem to be any obvious opens or shorts with any of the discrete components in the Horizontal section. Does the NT68P62-01 Microcontroller develop this problem?

First, check for reverse leakage (not just total short) in the modulator-diode half of dual rectifier D410, and in transistor Q411. If neither of these is leaky, then ring and check inductance of coil L410, check film cap C431 and C439, and ultrafast diode D418. Only then, go on to the microcontroller.

QUESTION NO. P912-9: Medion 1772xe (Acer 7377xe) monitor. Values require for R330 and R356 directly next to DST. Both are burned.

In the Repair Datasheet and schematic manual for Medion 1772e (Acer 7276e), value for R330= 22ohm 1/2W and R356=47K.

QUESTION NO. P912-3: I need the values of R717 and C721 on CTX 1565 monitor.

There is a good site with schematics at http//rv6llh.rsuh.ru/shema.htm This monitor is there as well.

When those two components die, the flyback transformer is defective, and also must be replaced.

QUESTION NO. P912-8: Samtron 55v monitor has no display and no 12V to ic401. Transistor A1281 (Q608) and cap104 (c110) short . I replaced A733, causing C428 (50v 10uf ) to blow and transistors Q403 and Q404 leak and short and a sound coming out. It does not start. When I open ic tda9302 Vcc pin6 the monitor starts but has one line and no sound.

First, Korean transistors are not "2SA" (Japanese) types. Your "A1281" is KTA1281, rated at 50V, 2 Amps, 1 Watt. A 2SA733 is only rated for 0.1 Amp and 0.25 Watt; a 2SA1382 will be a better choice. But your replacing Q608 with A733 is probably not the sole cause of your problems. It sounds like your TDA9302 IC is shorted, as well as those other components. Also be suspicious of a voltage regulation problem somewhere, that gives excess voltage on the secondaries.

QUESTION NO. P912-4: STX CM-451S monitor. Switch mode supply has failed. Going through startup / shut down sequence. Suspect 2SK2141, cannot find info on, or replacement equivalent. Transistor getting warm when power turned on.

I'd expect the fuse to blow, if 2SK2141 had shorted. 2SK2141 is an N-channel Mosfet, rated 600 Volts, 6 Amps, 35 Watts, TO220F case. Possible substitutes are IRFIB6N60A, 2SK1118, 2SK1507, IRFBC40A with insulator, & NTE 2379 with insulator. If the FET is not shorted, try checking for an overload off secondary diodes D106 through D110.

QUESTION NO. P911-7: Mag DX1595 monitor FCC Iawdx15fg . The Horizontal/Vertical IC TDA9103 has to be replaced because of arcing damage. In a number of previous answers reference is made to the STV7778S (I have a PDFfor this) . Is this IC pin and function compatible to TDA9103(PDF now removed by ST Microelectronics)?

To find out if a STV7778 can substitute for TDA9103, look at your board, and check whether pins 6 through 9 of the TDA9103 are being used. If not, then you can use STV7778 to replace TDA9103. The difference between STV7778 and TDA9103, is that pins 6-9 are no-connection in STV7778, but in TDA9103, these pins MIGHT be used for switching in different S-caps. However, many monitors that have TDA9103 do not use that function of the IC, anyway, and in those chassis, the STV7778 will substitute for TDA9103. Also, whenever a STV7778 was the original IC, a TDA9103 can generally replace it.

QUESTION NO. P97-5: Mag 1795 monitor. No HV, all voltages from power supply are OK(+42V exists), HV transistor OK.

Check if the 12V supply to pin 18 of IC701 (TDA9103) is low; this IC often shorts, causing loss of HV, and must be replaced.

QUESTION NO. P821-8: Gateway EV-700 monitor, no contrast, bright and contrast at max , picture very dim.

Check for dried up caps in the filament supply. Also check the following:
1. Filament voltage. Is it around 5 to 6.3V DC? Measure at CRT board.
2. By turning up the screen pot on the flyback transformer, image improve?
3. Probe the voltage at G1. Change the brightness control G1 change as well?

If answer to (1,2,3) is (no,yes,yes) - Repair the filament voltage circuit. (yes,yes,no) - Repair the brightness circuit. It has gone too negative. Can you hear the static crackle when monitor is first turned on? If yes HV most probably sufficient. Check B+ is sufficient and measure anode with HV probe if you have one and adjust if necessary since screen voltage is dependent on anode HV. After you have repaired the monitor, tune the screen voltage by holding the brightness control at half way and using a Nokia monitor test software (available on the net) to adjust the required brightness via the screen pot.

QUESTION NO. P87-1: LG Studioworks 44i monitor. R843 burned, I need value for it.

Check the flyback, R843 12K 1/4W, C787 1uF/50V. Also check all components all the way to the ABL pot. Check the HOT and the components around it as well. If HOT is OK then most probably the rest of the components are OK as well.

QUESTION NO. P810-10: Acer/ Aspire 77s monitor, the B+ goes high on, arcs so bad at the crt board, I cannot get any readings.

If all the surge protectors on the CRT board light up along with buzzing from the CRT neck, the tube is gassy and when the monitor is turned on the neck of the tube glows purple in color, you may need to get a replacement tube.

QUESTION NO. P831-7: HP M90 Monitor. The pins in the DB15 connector are bent. Where can I find a replacement cable?

If just bent - Use a long-nose plier to bend it back. Take your time and do this carefully. If broken while bending - Cut the cable a few cm away from the molded plug. Strip the cable to expose all the individual strands. Measure the continuity of each strand to the pins or stub. You will have a matrix of strand-pin. Purchase a DB15 plug and solder exactly following the matrix that you have just drawn up.

QUESTION NO. P815-6: LG Studioworks 76i monitor shuts off after 2 minutes. If unplugged then plugged back in, it will work for about 30 seconds. After doing this about 5 times, the monitor stays on. I checked degauss circuit and see no problem, even disconnected the degauss coil.

I repaired a similar problem on a CTX monitor which I had to turn on and off a few times to get it going and if I have signal going into the monitor when turning it on, it becomes very difficult to turn on. I had to disconnect the vga signal, try to turn on the monitor (hear static) and then plug the signal in. If your problem is similar to what I have described, check the HOT driver circuit. especially the resistor/s in series with the HOT driver transformer. The voltage feeding the driver transformer should only be around 24V generally. If it is too high (say around 85V, this was what happened to my CTX and the driver transformer and resistor got fried) then there is something wrong with the power supply side. I mod the driver circuit for my CTX monitor and use a driver transformer from a Wyse terminal and use the 24V supply from the vertical deflection circuit to drive the HOT. Unfortunately the monitor runs hot. If you have to do a similar mod, pay attention to the phase of the driver transformer.

QUESTION NO. P97-8: Acer 1768i monitor FCC JVP7176IE. shifts horizontally and folds over (right side of image on left edge of CRT) for resolutions above 640 X 480. OSD works fine and image is clear. Centering pot not effective but components around it are all OK. When use air gun to blow on L307, the image will shift back to the left for a short duration. Cooling L307 seems to solve the problem. I have not changed L307 simply because Acer here in my country will not sell me the parts. If someone can confirm that L307 is a likely cause of the problem that I am facing then I can get the coil rewound.

The model no. written on the label on the rear of the cover is 1768i but is really a 7176IE. While waiting for the answer I have managed to solve the problem (I am using the monitor to write this answer). Do not know why cooling L307 had the effect of shifting the image back to position but the cause was really C320, 100pF 2 KV cap. Since then also checked all the usual capacitors relating to this model i.e., C3950, C3951, C3952, C307, C353. A little more information for you guys - I also replaced the IC304 TDA4858 but the symptom remained. However, before I changed the cap (didn't know it was the cap then), I modified the circuit to pin#1 of IC304. I soldered a 68K 1/2W resistor in parallel with R395 27K increasing the voltage fed back to pin#1 of IC304. This pin is the HFLB (Horizontal Flyback). This mod actually solved the problem as well. If you have the circuit, I got mine from(www.oocities.org/monitorss/), you will see why I eventually changed C320. C320 dropped too much voltage and hence the amount that reached pin#1 of IC304 dropped as well.

First replace disk cap C320 (either 100 or 120 pF, at 2KV), because it can also cause a phase shift problem at higher scan rates (and cooling the L307 area may correct it). Also check for reverse leakage in D308 = FES8JT, and for high ESR on C307, C353, C3950/3951/3952. Often when L307 is truly bad, it has shorted turns or rings badly. If you should need to rewind L307, it is a 20 mH coil.

Check for a bad soldering joint on L307 (caused by the high temperature of the coil?). I soldered a 100k 1/4W resistor in parallel to R395 27k effectively making it 22k just for luck.

QUESTION NO. P96-7: Samsung 4bni monitor. What is the horizontal frequency and vertical frequency?

If your basic model is a Samsung CKA4227, the horizontal scan range is 30 to 55 KHz, and the vertical scan range is 50 to 120 Hz; maximum resolution is 1024 by 768.

QUESTION NO. P96-10: Viewsonic 1562ES-2 monitor FCC GSS15002. I need the value and part number of Q306.

The schematic for Viewsonic 1562ES-2 shows horizontal driver transistor Q306 as a Sanyo 2SD600K, and horizontal output transistor Q307 as a Philips BU2520DF.

QUESTION NO. P95-4: Apple M1823 monitor is bright green during boot but will return to normal after about 20 minutes. Occasionally flickers to green during use. Is green after wake up from sleep? Checked cabling, they are ok.

This fault can be caused by bad solder on small SMD resistors on the CRT board, that need reflowing or replacing. To access them properly, you generally first need to remove the three IC's with staggered leads, that are obscuring them. For your 'green' problem, I would first check the SMD resistor (2.7K) off of pin 5 of IC010, then check others.

QUESTION NO. P95-10: Unbranded model 1768i monitor FCC JVP7176IE. I need the value of C3950, C3951, C3952, IC303.

From the FCC#, it should be like an Acer 7176ie, where C3950, C3951, and C3952 are all 2.2 uF, 450V, 105°C electrolytic capacitors, and IC303 = LM7812, a 12V regulator IC.

QUESTION NO. P822-2: CTX 1565GM monitor. I need the value of Q413 (K890), R316, R458 and ZD402 (all burned).

The CTX 1562 has a transistor in the HV section numbered Q410 which is listed in the parts list as IRF630/890, so I suspect the IRF630 is it. Nearby components in that same circuit are a 15V 1/2w zener diode, a 2.2 ohm 2w resistor,and a 4.7k 1/4w resistor going to the gate.

QUESTION NO. P829-10: Proview PV-1768P monitor, only ticking sound. Found dead Q601, replaced with BU4522, failed after a few seconds. C603 is o.k.

Check b+ fet & caps.

QUESTION NO. P830-4: "Tiny" monitor with a LG CA-74 chassis in it (I need the Goldstar model number in order to order the service manual). The problem is that the HT rises to 155v-160v then dies back slowly. It then stays in a safety mode unless it is disconnected from the mains and reconnected again, it then repeats the above. There is no sign of EHT or output volts from the LopTx's secondary (no line drive ?????). Is this HT (B+) correct, it seems to be on the high side to me, pointing a finger at the SMPS. Also if the LopTr (HOT) is disconnected and a dummy load is used (or not used), the results are the same.

Being a 19" display, the LG Studioworks 995E (Model CB995CE, FCC# BEJCB995C) is not very 'tiny', but the FCC website does show this model as being a CA-74 chassis.

QUESTION NO. P830-3: HP A2094 monitor, replaced Horiz. output, and one FET, still no horizontal. No B+ on output transistor and component PS301 is reading open, component is stamped soc1000. Is this a fusable link?

Yes, SOC1000 is fusible link, rated for 1000 mA (1 Amp), from Sony, who is also the manufacturer of the HP A2094 chassis. A fast-acting 1 Amp picofuse can substitute.

QUESTION NO. P829-7: Mitsubishi FFF8705SKTKL monitor, loss of horizontal sync.

The Mitsubishi Diamondscan 17HX model can lose horizontal sync if the H. freq. data, stored in memory, gets corrupted. To adjust this data, you must enter factory mode, and a service manual is advised, as the procedure runs several pages in the manual. Try getting a service manual from a place like Electronicsrepair.net (www.electronicsrepair.net/monitor20.shtml), or see if your regional tech support will Fax you the relevant manual pages.

QUESTION NO. P828-7: Sampo Alpha/Scan SV KM-400A monitor. After a few minutes of power on, the monitor will be out of focus. Adjusting the focus knob at the flyback regain the good focus condition, but after a few minutes it will be out of focus again.

Drifting focus like this is usually caused by a defective focus block on the flyback.

QUESTION NO. P827-5: CTX VL710ST monitor FCC DBL1795SLU has a short circuit HOT (Q309) and also short circuit Q308. R393 is burnt beyond recognition. I need the value. Also, are there any other components we should check out before powering up?

In the schematic, R393 = 10 ohms, 2 Watts. Also check other components in the Q308 circuit, L305 = 5 mH, C334 = 47uF/250V, D302 = BYV26C, and ZD303 = 12V.

QUESTION NO. P824-10: Sony cpd 220vs monitor, the high voltage is ok for few seconds, orange light comes on and the voltage drops to zero. No shorts found in the power supply or in the high voltage. I replaced the flyback, same problem.

These have a flimsy main board. Check carefully for any cracks in the board, especially around the front support area.

QUESTION NO. P824-4: Gateway 500-069cs monitor operation from 220v mains. The power diodes lights up when switched on but the screen remains off. The relays and other sounds can be heard but the screen remains off with no static at all.

First, check for a broken PCB trace at the intersection of J165, R723, & the back corner of the FBT shield; if broken, jumper the break and resolder the shield, etc. into place. If there is no PCB break, and if your chassis is the TCO-95 version, with the two-section FBT, that FBT is a very high-failure component for giving no HV (no static).

QUESTION NO. P823-9: IBM 7095-593 monitor with a pincushion problem. I replaced the 47 Ufd cap near the flyback and also the vertical IC.

First check C539. If that is not the cause, try checking IC501 (either STV7778 or TDA9103).

QUESTION NO. P821-2: Axion CL1766 monitor. I need a source or sub for flyback transformer AT2097/02B - E 17865 - 31121TY - 99-40-6055-0007 - Phillips.

Nationwide (www.neiparts.com) is listing flyback AT2097-02B, on-line.

QUESTION NO. P821-3: Philips 17A, CM3800 monitor FCC A3KM053. Found same problem in archive but cannot find suggested resistor (R573) as locations have four-digit designators. Monitor powers on, degauss etc., syncs to PC OK, initial static crackle and HT present, normal low buzzing sound (quiet) - but no raster or video. Cathode glows as expected. Cannot determine if FBT is faulty or perhaps in some DPMS mode?

The archived answer looks like a typo, for my notes show the 1 ohm resistor near the yoke connector to be resistor 3570 (not 573). A lot of these units do get FBT problems.

QUESTION NO. P726-9: Goldstar Studioworks 74m monitor tripping on cold startup for approx. 30 sec. eventually starts up. Replaced PSU caps but did not help.

This is a very simple fault of [smps] type. Change all power resistance above 50kohm & 2nd s.w VR'S.

QUESTION NO. P87-7: LG Studioworks 7D (CA-38) monitor has no display, green LED on. SMPS is ok, HOT Collector 40v Dc, no G2 &G1 voltage, (Flyback) part no 6174Z-2002A.

This is a very common fault in LG monitors. Replace horizontal out to bu2508df & 2nd and flyback.

QUESTION NO. P817-5: Acer 7276c monitor, I need the value of R409 which is burned.

R409 = 10 ohm, 1 Watt, fusible.

Go to http//schema99.d2.cz/monitory.htm for free downloadable schematics.

QUESTION NO. P817-1: Compaq QVision 172 Model 454 monitor. I need the value of R120, and the part for the SOT23 transistor near R191. I see by another question ( NO. P114-3) that the surface mount transistor might be a 3F ie BC857B. I also have smoked R195 & R205 (values 215 ohm 0.5 Watt). Any tips for the common culprit for these failures?

R120 = 100 ohms, and near R191, there is an SMD transistor that is a 3F = BC857B. Also check R224 (0.47), C121 (0.01uF), D28 (BAV21), P-FET's T13 & T27, HOT T32, and especially check coil M3 for shorted/burnt windings.

QUESTION NO. P816-9: Gateway EV900-7000595 monitor. I need the value of R573 which is burned. What could have caused this?

R573 = 68K ohm.. First, check if D315 (HER303) is bad. If not bad, or if replacing a bad D315 does not prevent further damage, then probably the flyback transformer is bad.

QUESTION NO. P815-2: AcerView 76ie monitor keeps blowing the horizontal output transistor. Replacing transistor C5048 with BU 2527AF makes the monitor works for few minutes (display is normal) before display's black out. Transistor replaced is not hot when touch right after it becomes defective.

Check or replace disk cap C320 = 100pF/2KV (might be 120 pF), off the HOT collector. It is better to replace C320 with a 3KV-rated disk cap. Also replace C307 = 1 uF/50V, check the ESR on C353, C304, C3950, C3951, & C3952, and check FET Q303 for leakiness.

QUESTION NO. P810-1: ADI PD-959 monitor. Replaced failed LOPT , BU2520DF drive transistor & 2 ohm resistor. Powered up monitor, transistor & resistor taken out again. Found an earlier reference to same problem, also mentions Q567, a K1006. However, on the PD-959 model I have Q567 is not a K1006. What is the ident of Q567? SMPS is OK and LOPT O/P is ok.

I believe it should be Q563 (and not Q567). Q563 is the 2SK1006 that is associated with blowing the HOT and B+ resistor, when that Mosfet becomes leaky.

QUESTION NO. P82-9: LG studioworks cb775bn monitor FCC bejcb775b with poor focus. There is some adjustment using the focus block on the flyback, but video is still not crisp.

This monitor is prone to have CRT problems concerning the focus. We replaced a few under warranty. You can get the CRT from LG but it is cheaper to replace the whole monitor.

QUESTION NO. P82-6: Mitsubishi DiamondView 1772e monitor, I need to know what c326 and r329 are. They burnt out.

C326 = 270 pF/500V, and R329 = 10K ohms.

QUESTION NO. P82-1: ADI VD-484 monitor. Power LED blinks periodically when turned on with no change when VGA cable is connected. Traced to possible short in power switching transformer; Numbers are LT249A 002A (then on next line down) AXIS 9715, I need a source.

Try contacting ADI directly (www.adiusa.com/support.html; 1-800-228-0530).

QUESTION NO. P81-7: Sony GDM-500ps monitor when turned on high voltage comes on for a couple of seconds then goes into sleep mode. I have six of them in my shop.

These units are in shut-down mode. Best get the Sony manual, for troubleshooting codes, schematics, etc., Sony p/n# 9-978-594-03, from a Sony distributor.

QUESTION NO. P731-7: Compaq P110 model 630 monitor. I replaced the cxa2043q on a P110 but now when I press the ON-SCREEN display button, the display symbol appears on the left down corner but that is all.

If that was the SMD IC at location 007, then Sony DAS (digital alignment) will need to be run. If you do not have that software and apparatus, find a shop with this equipment, and software for the Sony GDM500 model.

QUESTION NO. P727-8: Is there a substitute for Samsung (sec) ka2141, a video preamplifier for color monitors used in Samtron 4bni models?

I know of no substitute for KA2141. If the problem is no video, first be sure the IC is not being shut off by inputs at pins 9 (contrast input), 10 (clamp gate input), 11 (blank gate input), or 20 (brightness control), and that Vcc is present at pins 5 & 16. If the IC is bad, after all, then try www.samsungparts.com for replacement parts of this chassis.

QUESTION NO. P726-6: Smile kfc ca6736sl monitor. I need the value of R111.

R111 = 10 ohms.

QUESTION NO. P725-6: ASTvision 7L monitor has a red screen with red back traces.

There is more than one chassis for AST 7L, check for an FCC number. If this 7L is the Capetronics chassis, check the LM1207 video preamp IC. On the Samsung chassis, first check IC105 (hybrid IC, MV17LO). If that one is not the cause, check IC102 (LM2427), and check for a short to the red gun in the CRT.

QUESTION NO. P724-8: Acer 7156 (acerview 56L) monitor, chopper fet Q604 and chopper ic both went s/c with resistors in psu going o/c, this was due to main smoothing capacitor dropping in value to 1uf . I need the value of R622 which is badly burnt.

R622 = 20K ohms.

QUESTION NO. P723-6: Mag DJ800 monitor sometimes starts and picture comes, but there is some "noise" on the picture and power supply is noisy. If I cut the track from T101 transformer it starts without picture and then if I connect tracks picture comes always. It seems that something takes current too much and power supply shutdowns.

This monitor is prone to flyback problems. Replace flyback by TF26V0003S0 available from MAG Innovision, also resolder L105 and T501.

QUESTION NO. P720-10: Hewlett Packard d5259a monitor, OEM Tatung c7b. I need the values of D802 and R430.

The Tatung C7B schematic shows D802 is 1NU41, which is a 1000V, 1 Amp ultrafast diode (NTE 575 should be similar), and R430 is 15 ohm, 1 Watt.

QUESTION NO. P717-4: KTX Topscan CAE-364SG monitor originally was intermittently blue. After checking for dry solder joints the green electron gun was working but the red was still not working, unless the monitor was on for around 30min, then it would return to normal operation.

Check L203 and the old conductive glue on the crt board.

QUESTION NO. P719-7: Acer 7156S 411 monitor after about 15 minutes of warm up, the focus has gone high, text is unreadable. If I adjust the focus, it will work perfectly again. I checked the horizontal circuit and changed all the leaking elco's but this does not help.

With your description, change the fbt.

QUESTION NO. P720-4: AST 4N monitor FCC CSYSC-428PT during the CPU boot-up the display is horizontally shifted (image appears side by side). When it goes into the Windows mode there is horizontal tearing (image moves diagonally across the screen without stopping). I checked the cable, adjusted VR403 (H-Hold control) and changed the refresh rate of the display card but no change. I also replaced IC101(LM1203N) and IC401(TDA4850) but still no change.

Look for an ic 74xx86 and change it with exactly the same type. It is associated with the horiz and vert signals coming in from the video card from the computer.

On Compaq's with that same FCC#, this is often caused by bad solder on IC202, a 7805 IC in the middle of the board, so check the components in that circuit.

QUESTION NO. P719-10: KDS VS-7/EVOKD-1730 monitor suffering from blurry display problems. I see three trim pots on the main board, but the manufacturer was not kind enough to mark their function on the board. The pots are marked as VR401, VR801, & VR902. Does anyone know if any of these might be a focus, or sharpness adjustment?

Those trimpots are not for focus. It is typically the case that the controls for focus are on the FBT itself. In this chassis, I believe that the FBT has controls for both the horizontal and vertical focus. If those controls cannot improve the focus sufficiently, check out the CRT with a Sencore analyzer.

QUESTION NO. P717-1: HP D2818A monitor after three to four minutes warm up, the display becomes reddish and the horizontal line (raster line) comes out.

Check out hybrid IC, IC105, on the CRT board (might try heat gun or freeze mist), as well as checking for cracked solder on the pins.

QUESTION NO. P716-10: I need a supplier for oem Princeton parts such as By329-1500,SSS7N60A and 2SC5386 for Princeton Ultra 72e.

Nationwide (www.neiparts.com) is listing all those components. Note, 2SC5386 is a Toshiba transistor. But if yours is marked C5386, and made by Samsung (SEC), rather than Toshiba, then the correct number is KSC5386, which is a different device.

QUESTION NO. P713-8: Goldstar Studioworks 45i monitor FCC bejcs486 Chassis CA-51 had no video. High voltage and raster O.K. I found that the video amp IC301 on the CRT board had no VCC applied to it. IC302 supplies VCC to IC301. I jumped out IC302 with a resistor to verify IC302 defective, video came back, good. I cannot Identify IC302 correctly or find a supplier for it. Markings are KIA76L, it has three pins, it looks like a transistor, and the case is square.

Your package description sounds like a voltage regulator IC from Korea Electric Corp. If so, that part number is incomplete, and probably why it could not be found. I suspect it is actually KIA78L (not 76L), and underneath the KIA will be a suffix for the voltage (such as 08.... for 8 VDC output). The datasheet for the entire KIA78L series is found at http://www.kec.co.kr/databookV3/Pdf/KIA/78L0524BPV.pdf. These regulators have circuits that will shut them down if either power (0.8 Watt) or current (0.15 Amp) maximums are exceeded, so first be sure your device is not in shutdown. Also, their pinout (Out, Gnd, In) is backwards from the usual for 78L regulators. If you cannot figure out the output voltage for your IC302, it should match the Vcc for the IC301. For example, the datasheet for MC13280/81/82 shows their Vcc is 8VDC, and so IC301 would be KIA78L08. A Zetex ZSR800 might sub a KIA78L08, but most 78Lxx devices are only rated for 100 mA, so a 78Mxx device might be a better sub than other 78Lxx.

QUESTION NO. P712-10: TTX TTX-5700 monitor FCC EVOKD-1700V; need to know the values of R833, R829, and ZD803 in power supply.

In a Princeton brand with the same FCC#, R833 = 560 ohm, R829 = 220 ohm, and ZD803 = 12 Volt zener.

QUESTION NO. P79-1: Hyundai HT-5870C monitor. Is there a factory service mode for color adjustments? We have a lot of these units to service which have been converted to Touchscreen and it is worth replacing the CRT but we cannot adjust the colors due to lack of analog controls.

This worked on some Hyundai 7870A Touchscreens; perhaps the 5870's are similar. On the side of the main board, there was a connector for digital alignment. One pin on that connector, 'MF', when shorted to ground, permitted the chassis to enter service mode.

QUESTION NO. P79-5: Dell d825ht monitor has vertical foldover on the bottom portion of the screen. I replaced the vertical output with no luck.

Is there a solid -10 VDC on pin 4 of the vertical IC? If not, try checking components on this line, such as C401, C403, D653, C653, and L653. Also, pin 2 should be +16 VDC.

QUESTION NO. P79-7: Smile CA6736DL monitor FCC GBVCA6736DS. I need a source or sub for flyback transformer FEA 527, Samp 9740 ; E1596 58 ; 15-EO24-0419 ; SE7A 02D4 FM 1057.

Try Nationwide Electronics (www.neiparts.com) for flyback FEA527.

QUESTION NO. P75-9: Viewsonic 17g monitor FCC acj93312116. I need the part number of d510. It is a smd and has M1U on it. Can I use two decrete diodes and, if so, what can be used?

Panasonic SMD diodes marked "M1U" are series-connected dual Schottky's, rated at 30 Volts and 30 mA (150 mA surge) per diode, Vf < 0.4V @ 1mA. Since you did not describe the exact SMD case, your diode is either a Panasonic MA716 (SC-59 case) or MA742 (SC-70 case). Digikey (www.digikey.com) lists both MA716 ($0.61) and MA742 ($0.64). These specs are similar to the Philips discrete Schottky series BAT81, BAT82, BAT83. Or perhaps SD101 (Diode, Inc.) might be tried.

QUESTION NO. P75-5: How do I open the case of an Apple ColorSync 17 inch Monitor without breaking the plastic tabs?

If you mean the covers over the Torx screw channels on either side of the rear housing, these must be squeezed using one hand, until they bow outward just enough, for the center to be grabbed using the other hand, and removed. A tool will gouge or snap them. Removal of the rear housing is a complicated process. I strongly recommend getting the document for the ColorSync 17 from www.traffictrak.com/ServiceManuals/ before proceeding further, and following the disassembly instructions carefully.

QUESTION NO. P612-7: Power Computing/Sony GDM-20F03 monitor FCC AK8GDM20F03. Powers up, then two orange LEDs flash on/off. No HV, no video. Partial solution: On the main deflection board, in the P/S section, check/replace Q645, C4833/ECG2582 (all junctions shorted); Q647, C4833/ECG2582 (all junctions shorted); R638, two Micron 0.1 ohm, 1/2W wired in parallel (both open); and away from the P/S, IC402, LA6500 (exploded). After replacing the above parts, green LED came on, HV began to come up, then IC402. LA6500, exploded again and the (left?) orange LED flashed on/off (the other stayed off).

Electronix Supply House 800-223-3205 has a diagram for Sony AK8GDM20E01 for $29.95. Maybe it is similar to your unit.

GDM20F03 is a different chassis from GDM20E01. Get the Sony service manual for the GDM20F03 from a Sony distributor, Sony part number 9-978-509-01.

QUESTION NO. P67-5: Acerview 79g, 7279g JVP7279g monitor is dead. Replaced Q314 (hot) Q321 (f640) in main pcb and D701, D713 (2nu 7.l), D611(1n5388b), still no power. Since I cannot get 1n5388b(5w zd), I replaced with a rectifier, is it the reason?

Other than D611, the replaced components are in the 180 Volt rail and Horizontal deflection circuit (Q314 is for deflection), so also check RF3958 = 1 ohm/1 Watt, fusible. Since Q321 also blew, check components in line with it, including D315, D316, L303, L304, R346, R363, and R3820. It was a mistake to have replaced the 200-Volt zener at D611 with a plain rectifier. Since D611 is in series with opposing diode D612, now no current can flow in either direction, similar to having left D611 open-circuit altogether. If you powered up this monitor with a rectifier installed at D611, inductive voltage spikes from T601 may have damaged Q602 and associated components (including IC601), so check those components. If you cannot get 1N5388B, try replacing D611 with an NTE 5166A replacement Zener. Another possible alternative for D611 could be a transient voltage suppressor, like 1.5KE200A or NTE 4988.

QUESTION NO. P67-10: ADI PD-959 monitor powers up, relays switch and front panel LED responds as expected when attached to a PC but no filament or HV. No burned components or cracked traces.

Found the answer I was looking for in the archive - see P525-3. Replacing the transistors without the flyback just resulted in a failure a few hours later. Also watch the heatsink on the K1006, it is not flat and only makes edge contact with the transistor body.

QUESTION NO. P618-7: KTX CAE565SG monitor has no horizontal width adjustment and is too wide. Found q304 leaky but cannot obtain replacement. It is a FS12UM fet in a TO-220 case.

FS12UM is a 12 Amp Mitsubishi FET, but that number is incomplete. There will be a suffix, to indicate the voltage rating, (in 50V increments). Yours is probably FS12UM-5, which is a 250 Volt, 12 Amp, 100 Watt device. Possible substitutes for that device are ST Micro's FET, STP12NB30, listed by Mouser (www.mouser.com), or perhaps IRF's IRF644, listed by Digikey (www.digikey.com).

QUESTION NO. P618-8: Several Dell P1728U monitors which have a non standard pin configuration. Where can I get cables? I really do not want to open them all and move the pins around.

The Dell P1728U is a Mitsubishi-made chassis, and Mitsubishi uses a nonstandard pinout. You might get cables from a Mitsubishi supplier, or check with KMR Technical Services (www.kmrtech.com), about their cable VCDB-003.

QUESTION NO. P614-7: Techmedia TCM-1764S monitor blows fuses. I found a short on the drive FET for switching supply. Transformer believed to have short in primary. The numbers on the transformer (top to bottom) are TCM-1764S then EH-9705. I need a cross or source for this transformer.

It is not usual for the switching transformer to be short circuited. The usual reason why the switching FET in the power supply goes short circuit again is because of a defective 3842 IC. Usually the resistor.022 ohms in the FET's source goes open circuit as well so check this.

QUESTION NO. P613-5: Mag DX17F monitor is not providing power to the main board and supply board is making clicking noises. I removed R361 and degaussing relay stopped clicking but a slight clicking still occurred, removed Q301 (NEC K1794) and clicking stopped. Measured voltage at junction of C303 and R304 and got 346Vp-p 210Vrms. Measured ~60.1Hz on pin 4 of IC301. I searched for the K1794 part on the net - NEC was useless and no mention of the part on the net at all. What is an acceptable replacement for this FET? Am I on the right track?

The full number on that NEC FET is 2SK1794 (might sub NTE 2377), but it's probably not part of your problem. Check if HOT Q109 is shorted. If yes, check/replace C120, C123, Q116, D116, R177 = 1 ohm/2W, R181 = 120K/2W, and replace L105 if it is discolored/shorted or rings bad (L105 is carried by many monitor repair suppliers).

QUESTION NO. P614-4: ADI Microscan 5PD, model VD-697 monitor, no FCC. When first brought in, the power LED turn YELLOW when power on, but no HV. The HOT (Q805), 2SC5515 (Panasonic) was shorted. As I cannot find the original part here, I replaced with a 2SC3997 which has a higher rating on the IC. Now the power LED turn to GREEN and stay on, but the HV fire up and cut off after 2 seconds. No display, the green LED is ON.

It sounds like FCC# BR8VD-697P, in which case, Q805 (2SC5515) is for the horizontal yoke deflection. Check D924, for the 200V line, R511 = 2.2 ohm/0.5W, also the B+ Regulator FET Q501, and associated components ZD501 & R501.

A good tip in these sort of cases is to unplug the tube panel, because usually some protection has taken over. ie. ABL or X-RAY. If it stays on this will give you a chance to fault find.

QUESTION NO. P614-5: Compaq V55 612 monitor. I need a sub for IC KA2S0680 in the power supply.

One can substitute KA2S0880 for KA2S0680. For either of these IC's, try LJ Enterprises (www.ljent.com; may be mis-spelled as KA250680, etc), B&D Enterprises (www.bdent.com), or Nationwide (www.neiparts.com).

QUESTION NO. P614-2: Acer 7276e monitor, the power light goes on then cuts back to half intensity then fades out completely. The neck on the tube flashes a bright light and fades as well, all within 15 seconds. I disconnected all cables except the flyback from the motherboard but get the same results.

If HOT Q302 has shorted, or microfuse J013 is blown, check the components listed in the answer for question P68-5, as well as Q316. Besides microfuse J013, there are several other microfuses to check (F701, F702, F703, F704; FR101). A shorted vertical IC (TDA8351) or video driver IC (LM2405) are fairly common, also.

QUESTION NO. P613-9: HP Pavillion D5258A monitor chassis code C5B. Need the value of R865.

My schematic for Tatung's chassis C5B is extremely poor, but if R865 is the resistor coming from pin 6 of the 3842 IC, it appears to be 27 ohms, 1/4 Watt.

QUESTION NO. P613-3: Sony GDM-20SE2T monitor, bright raster showing retrace lines. Is this unit similar to the GDM20E03 and should I look for the infamous IC420 (CXA1907S)? What should a reasonable G2 voltage range be?

Since the FCC# is AK8GDM20E03 for the 20SE2T, it should be clear that GDM20E03 is similar, and yes, IC420 is a potential cause of that problem. Depending on the G1, CRT, and high-impedance probe, a 170-350 Volts G2 voltage range might be seen, in good units.

QUESTION NO. P612-6: CTX x70 monitor FCC dbl1795vl. I need the value and part number of Q401.

For FCC# DBL1795VL, I show Q401 as Mitsubishi's FS3KM-18, an N-channel Mosfet, rated 900V, 3A, 30W, Rds[on] < 4 ohm. Try B&D Enterprises (www.bdent.com) for the original, or possibly get Toshiba's 2SK2700T from Digikey (www.digikey.com).

QUESTION NO. P518-1: I need a source for flyback transformers and other parts for Pionex monitors.

Get the FCC ID off the back of the monitor then go to the fed site (www.fcc.gov/oet/fccid/) and look up the id number, it will tell you who actually built the monitor. There is also a site for the UL code that will get you the same info.

QUESTION NO. P68-5: Acer 7276e monitor w/ vertical deflection failure. Cannot find source or replacement for Q301 bss89 fet. Also need value of R329.

R329 = 10K; Q301, FET BSS89, can be replaced by a Philips BSN254 (not BSN254A). Nationwide (www.neiparts.com) is listing BSN254 and BSS89, online. Before going further, replace the root cause, C327 = 220 pF/2KV (3KV replacement preferred). Also check R326 = 3.9K, R328 = 4.7K, R241 = 10K, ZD210 = 5.1V zener, J013 (3 Amp picofuse), D308 = UG4D, HOTQ302 = 2SC5048, and IC201 = TDA4858.

QUESTION NO. P68-8: KDS VSx-7 monitor, the power light comes up, but no image. R902 and R901 burnt. I need the value and are these the only parts that are defective?

The FCC# should be EVOKD-1730 for this KDS model. R901 = 27K ohm, R902 = 12K ohm. These resistors burn because the flyback transformer KFS-61411A is bad; get a replacement FBT from KDS (Korea Data Systems). Also check R903 = 47K, R904 = 12K, Q901, Q902, and if R904 has also burned, then check or replace IC401.

QUESTION NO. P523-4: Gateway EV900 x19001 Monitor will not power up. Previous repair attempt abandoned and R773 removed. Anyone know the value?

R773= 2.7K ohm, .25watt.

On my chassis, R773 begins with a brown band so it is not 2.7k (the rest is burnt).

QUESTION NO. P67-1: Hewlett Packard D2818A monitor FCC A3LCMG737. Need values of Q408, R453, R455, D418, burned.

R453 = 22 ohms; R455 = 2.2 ohm (fusible); D418 = 1N4148; Q408 = IRF740. Also check D417 = UF5404, if these others were damaged.

QUESTION NO. P67-8: Daewoo cmc-1707b monitor. I need the values of R468 and R462 which are burnt out on ABL circuit and a model number for the FBT.

R462 = 4.7K, R468 = 3.3K. The FBT should be either ZTFJ54006A or FFA87017U, but before replacing, check that the HV anode has not shorted within the CRT itself.

QUESTION NO. P531-8: Samtron 4Bi monitor (Basic CKA4227L), FCC A3LCKA422, initially the image was displayed on the center of the screen and was approximately 2 inches in height and 4 inches in width and also two bright horizontal lines on the top and the bottom of the image. All adjustments on the panel except for contrast and brightness were inoperative. I replaced C6271000uF 16V, C306470uF 16V, C308470uF 16V and vertical IC301TDA9302H.I now have normal horizontal width which can be adjusted but the vertical height remains the same ( i.e. 2 inches ) with the two bright lines. Now the controls on the panels are O.K. but whatever vertical adjustments I try to make seem to take effect in between the two white lines as if the lines were a limiting frame of some sort without any changes to the image's height. All the capacitor I replaced had low capacitance.

Check for a leaky/shorted diode between pins 2 & 6 of the TDA9302H, or a bad capacitor between pins 3 & 6 of the TDA9302H. Either of those faults could prevent the vertical output at pin 5, from having full deflection voltage. If these are OK, see if the vertical output signal from IC401 is providing a good sawtooth waveform.

QUESTION NO. P517-1: Daewoo CMC-1707B monitor. I need values for R468 and R469 which are badly burnt.

According to the schematic R468 is 3.3k and R469 is 75k 5%.

QUESTION NO. P531-1: Packard Bell 2020 monitor will not power up. SPDT relay clicks approx twice per second, with power LED flashing in time with it. After approx 30 seconds the clicking/flashing slows down and stops altogether and power LED glows solid yellow albeit dim but unit is completely non functional. I checked the relay and surrounding electrolytics but all seem OK.

I checked through the high voltage circuit and found a shorted horizontal output transistor. The damper diode checks out fine. I replaced the transistor and the monitor has been working fine ever since.

QUESTION NO. P525-3: ADI pd-959 monitor cuts the feeding. Had bad Q831 (BU2508DF), believe this is not original. Also bad Q567 (K1006) and R866 (2 ohms). Replaced these components and powered up, blew Q831 again.

Q831 is BU2520DF, but even the original Q831 may still blow. The PD-959 is known for getting defective flyback transformers, that destroy those components. If BU2520DF is not the fix, the FBT numbers are FEA662 or LZ250A000P. If a US source is needed, try Nationwide (www.neiparts.com) or LJ Enterprises (www.ljent.com).

QUESTION NO. P525-7: Daytek DT-1731D monitor, FCC EWBOC17DB02; need the value of R634.

R634 = 3.3K ohm. But if R634 is burnt, the FBT is probably also bad.

QUESTION NO. P516-7: ADI Microscan VD-697 monitor, blue & green show fine but red is missing from both normal display and the OSD. Internal Signal connectors appear fine.

Replace the drive transistor (most probably on a heatsink) for the R gun on the chroma board. Also check the big resistors on the chroma board for O/C.

QUESTION NO. P54-3: Sony GDM-400PS monitor has a wavy picture in all mode. Is IC007 CXA2043Q causing the problem?

Yes it is IC007 causing this fault. I repair a high volume of these monitors badged as Compaq. It is the deflection process I.C. and this is a common fault.

QUESTION NO. P521-9: Applevision 750AV monitor needs a flyback transformer. I need a part number or size equivalent. I know it is made by Sony.

If this is an M2942 chassis, the flyback is number Y265065C.

QUESTION NO. P522-4: Compaq v700 monitor dead. AC coming in is ok, the power switch is working ok. I have to bleed cap c907 or mt huntron keeps blowing a fuse.

There are several CTX chassis called VL700, so without the FCC number, my info may not be for your chassis. For FCC DBL1769E, I show a fix for 'dead', changing the HOT Q313, P-FET Q306, R362, and cap C340. For FCC DBL1765S, a fix for 'dead', caused by a tiny shorted 0.01uF cap, C671.

QUESTION NO. P522-7: Techmedia TCM-1764S monitor blows fuses. Checked bridge rectifier and filter cap both are good. Worked my way to the transformer where some kind of switching transistor?? is on the input. This has a dead short between all leads; the number on the part is in the following order top to bottom 2 N 72 k2333. What are the specs/pinout or cross for this transistor.

This sounds like 2SK2333, a Shindengen N-ch. MOSFET, TO220F with pinout GDS, rated 700 Volts, 6 Amps, 50 Watts, Rds < 2 ohms. Possible subs include FS7KM-14A (or -16A) or FS7TM-16; or, with insulation hardware, FS7UM-14A (or -16A) or STP6NB80.

QUESTION NO. P522-9: Princeton E070 monitor. The flyback seems to be bad, I replaced the HOT a few times. I get a picture on the screen for about 3 seconds before the H.O.T. goes out (burns up). I need a source for the flyback. I checked the power supply area diodes, resistors are good. Only other thing is a diode could be failing under load.

If this Princeton is FCC EVOKD-1730, the chassis was made by Korea Data Systems (KDS), and the flyback is KFS61411A. You could order this from Princeton itself, or Nationwide (www.neiparts.com). If these are not options, KDS could be contacted directly, and they do sell the flybacks (often more cheaply) for this FCC chassis, but ONLY for KDS models, like the KDS VS-7, not for Princeton OEM's. Be advised that KDS has issued a modification on this chassis, if the flyback is replaced, changing a number of resistors, diodes, and capacitors, to improve flyback survival. Tech support should be able to provide this information, or you could get Upgrade Kit#4 for the KD1730 chassis, from Nationwide.

QUESTION NO. P514-1: I need a North American supplier for IC M0C2A60005, from the power supply section of an Apple monitor.

I believe this refers to MOC2A60-5, typically used as AC1 in the Applevision/Colorsync Displays. This Motorola "Power Optoisolator" (a type of solid-state relay) has a Triac rated for 2 Amps output, but this device has disappeared from the market. If you wish to purchase many pieces, it may be worthwhile inquiring from DERF (www.derf-intl.com). If not many devices are needed, Omron makes a version of their G3MB solid-state relay, the G3MB-202PEG-4-DC20MA, which is a cross for the MOC2A60 types. Omron has direct ordering available, in North America, via their website (www.omron.com). If the drive current being applied to the Omron's IR-LED should be a bit low, to operate a given device, try reducing the value of RP31 somewhat.

QUESTION NO. P517-7: Compaq 480P monitor FCC GZM1323. Need a source or a replacement for a V815 (THD400 transistor), located in horizontal circuit.

THD400 is not obtainable, but Fimi has suggested the following substitution. Change V815 from a THD400, to 2SC3998, and also do the following modification. Install another retaining clip and mica insulator (with heatsink grease) on new V815. Remove V841, and capacitors C883 & C884, from circuit. Install a jumper in place of C884.

In response, performed the modification but now the new transistor runs extremely hot and monitor will eventually shut down.

QUESTION NO. P515-1: Hewlett Packard 5259A monitor Chassis C7B has no width or pincushion adjustment. Thanks to your tip, I found D434 (DMV32)leaky. My problem now is finding a replacement. Who carries this part and is there a substitute?

DMV32 (DMV32A, DMV32B, etc) dual diodes are in a TO220 case, rather than the TO3P or TO3PML cases often used for such duals. A possible sub is the Sanken FMP-2FUR, but it may be even harder to find. Try LJ Enterprises (www.ljent.com) or Nationwide (www.neiparts.com) for DMV32B.

QUESTION NO. P515-4: Need the value of R569 in Gateway CPD15F13 monitor.

R569 = 68 ohm, 1 Watt, 5%, flameproof.

QUESTION NO. P515-10: Nimble NB-1726VQ monitor I think it was made by KFC Kuo Fong CORP. It was blowing the main fuse. I found transistor at location Q506 in the power supply shorted out. The part number on the transistor is NEC K2141 I can not find a cross Ref # for it. Is there any thing else I should look at before I replace the transistor?

The full number of this Mosfet is 2SK2141, so inquire for it using the full number. This FET is rated at 600 Volts, 6 Amp, 35 Watt, Rds[on] < 1.1 ohm, Ciss = 1150 pF. If your suppliers do not stock 2SK2141, you could try IRFIBC40GLC, or an IRFBC40A with insulating hardware. Digikey Corp. (www.digikey.com) carries the IRF lineup. If the FET was shorted, I would check any resistors or diodes/zeners off the gate lead, and if any of these are bad, also check the FET driver IC. You might also ring the primary of the SMPS transformer, in case of a shorted winding.

QUESTION NO. P57-2: Compaq P110 model 630 monitor, the lower half stretches and bounces and eventually puts the monitor into standby. Also, is there a Sony crossmatch?

I believe this is a Sony N3 chassis, similar to the Sony GDM-500PS. Check out the CXA2043Q IC.

QUESTION NO. P514-4: Mitsubishi Diamond View (1772E) monitor FCC JVP7276E. I need the value of c327.

C327 = 220 pF/2KV. You might replace this with a 3KV-rated capacitor.

QUESTION NO. P510-1: Goldstar StudioWorks 76i. Replace D915 which was shorted and CVA2422 that was burned by a new average diode substituted and for a new CVA2422TL. In less than 5 seconds the CVA2422TL burned again and the diode little time later. The exits of the supply power for 175V and 80V were very low.

If by 'average diode', you mean a standard-recovery rectifier, that would be too slow. I believe D915 is a fast-recovery type rectifier, Trr < 250 nanoseconds. Also check the electrolytic filter capacitor off pin 11 of the CVA2422T, and the filter capacitor off the cathode of D915, for damage.

QUESTION NO. P59-7: I need the value of R935 on a Daewoo CMC-710B monitor mainboard.

R935 = 82K. It is part of the ABL circuit, off the FBT, so the FBT is suspect, if it burned.

QUESTION NO. P58-5: I need the part number of Q527 in a Sony CPD-15F13 monitor.

The CPD-15F13 is usually a Sony 15SF1, in which case, Q527 = 2SD1640Q (Sony p/n# 8-729-023-28). This is a diode-protected NPN Darlington transistor, Vcbo = 120 Volts, Vceo = 100 Volts, 3 Amp, 1.2 Watt, TO-126 case. The 'Q' indicates a gain bracket between 4000 and 10,000. Besides Sony distributors, 2SD1640 itself is listed by MCM Electronics (www.i-mcm.com), Dalbani (www.dalbani.com), Nationwide (www.neiparts.com), and others.

QUESTION NO. P57-4: H.P. D5259a monitor has no width or pincushion control. All caps check OK and have found no shorts or opens.

First, HP has been marketing different chassis under the same model numbers, and D5259A is one of those models, so you are inviting problems if you do not also provide the chassis code (or FCC). For D5259A chassis C7B, I would check for reverse leakiness or shorts in Q470 or the modulator diode half of dual diode D434, and check out L471. If this gives no help, check the E/W signal out of pin 24 of IC401 = TDA9109, and if bad, try replacing the IC. If your D5259A is chassis C711, try checking D702 & D710.

QUESTION NO. P57-7: Gateway ev700 (made by LG) FCC BEJCB775B. I need a source for FBT 6147z-1012c.

The FCC corresponds to an LG chassis CA-65, similar to an LG CB775BN or Studioworks 775N. Try an LG distributor with the FBT number, but it should be 6174Z-1012C, not 6147Z. Nationwide Electronics (www.neiparts.com) is listing flyback 6174Z1012C in their online inventory.

QUESTION NO. P53-1: Sony CPD-17SF2 monitor was totally dead. After replacing HV trans, both led blinking. No 12 DC, but 145 V and 75 V exist. Replacing IC602 (12 v regulator) did not help.

Check Mosfets Q503 and Q510, damper D501, and also check small signal diode D596 (near FBT) for reverse leakiness; a 1N4148 can replace it. Some capacitors may be bad in this area (start with C525, C540, C541, C592). Check for any blown fusible resistors in the SMPS transformer secondaries, and for any hairline cracks in the PC board traces.

QUESTION NO. P411-7: NEC 5FG monitor switches on with green light lit , no EHT but have outputs from power supply as follows: brown/184v red/90v orange/28v, unsure if these voltages are correct.

If this 5FG is JC-1741UMA, and you are measuring at K1, K2, K3 of power connector CN-K, I'd expect to see 180V, 90V, 30V nominal.

QUESTION NO. P51-8: Digital Research 0711-03 monitor, cannot adjust width (too wide) or pincushion. I tried several caps.

Check Q203, Q204, Q205, Q206, D107, C108. Some transistors might merely be leaky, not totally shorted/open.

QUESTION NO. P51-7: AcerView 7176ie monitor, on start up a green tint appears and after a short warm-up (approx 2 minutes) monitor resumes normal operations. Replaced Caps 3950, 3951, 3952 and Cap 353. Repair fixed intermittent video flickering but green tint is still present at start up.

Check for bad solder connections on the video board, especially on the video connectors and on the grounds for the video shield. Also check C110, C101, C102, C104, C175, and the nonpolarized caps C111, C131, C151, for low value and/or bad ESR.

QUESTION NO. P430-2: Daytek DT-1431 monitor, the screen has no display, no raster and the power LED is blinking. All transistors checked good.

Check the screen, brightness, and contrast controls. If that does not work check the flyback transformer and recheck the horizontal output transistor.

QUESTION NO. P427-1: Nec Multisync 4FG monitor powers on with solid GRN LED. Bad static crackle on power up as the display flashes for a split second. Part site might also help.

Start by checking under the electrolytic capacitors for leaked fluid, conducting voltages to various places and eating PCB traces. For that symptom, start with C557, C556, & C793, but many can leak. Other common leakers include C561, C554, C564, C516, C517. Clean up any leakage well, and repair any blackened traces that got eaten by fluid.

QUESTION NO. P427-2: Viewsonic p815 monitor (manufactured by Panasonic). I need to find a source for a Motorola MHW3528 (triple video driver amplifier). This hybrid ic contains the circuitry to drive the color guns of the crt and is located on the crt board. I have tried most of the sources listed in these faqs, but have had no luck in finding a supplier. What other monitors/televisions use this part (so that I might find a OEM source)?

Nationwide (www.neiparts.com) lists MHW3528 in its online inventory. P815 is a Panasonic GV3 chassis, so check for this IC in other GV3's, like the Panasonic P110.

QUESTION NO. P427-5: Sony cpd 200es monitor. I suspect your advice that the main MPU is bad since the power LED flashes on and off. Where may I locate a replacement for IC901? The part I have is ST7272N5B1/CUS or Sony-47-16 422AH9740Z.

Contact a Sony distributor, for Sony p/n# 8-749-014-36. This version replaces the original Sony p/n#, which was very high in failure rate.

QUESTION NO. P427-6: KDS VSx-7 Visual Sensations monitor FCC EVOKD-1730, power light comes up, but no image. R304 burnt beyond recognition. I need the value and is this the only part that is defective?

A Princeton here, with FCC# EVOKD-1730, had R304 = 4.7 ohm, 1/2W. Also check D406 and IC301. There was a design flaw in FCC# EVOKD-1730, that can damage R304 and IC301. KDS has recommended modification of the chassis, to replace J301 with two 1N4002 rectifiers, wired in series, and replace R330 with two resistors wired in parallel, with values of 180K and 200K ohms. Check if KDS VSx-7 has had this upgrade.

QUESTION NO. P424-7: Acer 7257c monitor has pincushion problem. Changed ic 201 tda4858, problem not solved.

Try checking transistors Q302 and Q303 for short or reverse leakiness; you also might check bipolar capacitor C316.

QUESTION NO. P411-1: CTX VL700 monitor. Need alternative type for transistor Q415 marked as type F444 but cannot identify this or find an equivalent.

I think the transistor you are referring to is a SGSF444 made by ST (st.com) which I believe it is obsolete. I do not know of a substitute.

SGSF444 crosses to ECG2324 according to ECG212S Master Replacement Guide.

QUESTION NO. P424-3: Hewlett Packard D3859A monitor has vertical tearing across the entire screen and I 603 vert.out. IC TEA8172 gets extremely hot. Replacing it did not help.

Check the capacitors around IC603, especially C626 off the input. If there is ripple or noise on the power rails for the IC, this can also cause problems, so check the filter caps. Also check zeners ZD601 & ZD602. Sometimes, screen noise can come from a faulty (noisy) KA3842 IC in the Power Supply.

QUESTION NO. P419-7: What is the value of R608 in Digital PCXAV-TZ (Chassis CA-52) monitor?

Electro Sound carries this resistor and capacitors Part # 1-202-933-61/11. 800-441-6110 in New Jersey.

QUESTION NO. P423-1: Gateway 2000 EV500 500-069CS monitor Chassis CA-46, intermittently will power up, then enters shutdown. Can hear arcing sound when unit enters shutdown. Arcing sound leaves when unit works. Ftb? Crt? Part# for ftb-6174Z-1002A? Ground straps are connected, cannot see any visible arcing when lights are turned off. Strong guns when working.

There are two versions of this chassis. One version has a two-piece flyback transformer, with an HV diode module mounted next to the FBT. These are very common-failure devices. LG Electronics (formerly Goldstar) distributors can provide them, using your flyback's number, but they are rather expensive.

QUESTION NO. P423-7: HP Pavillion D5258A monitor is dead. I need a source for 24lc211 IC which I suspect is the cause.

24LC1I is an I2C serial Eeprom (www.microchip.com). So, if you indeed do need this IC, you probably need it properly pre-programmed. This requires knowing the OEM manufacturer (HP is not the OEM), and their corresponding model#. However, be advised, that HP has used several different chassis (and from different OEM's) in D5258A, and also D5259A, Pavilions. I personally know at least four different chassis for D5258/A (could be more), from OEM's like Philips, Daewoo, and Tatung. You'll need to use the FCC number off your version (or failing that, the chassis code), to locate the OEM manufacturer and their corresponding model, to get the properly programmed IC from them.

Firstly it will probably not be the EEPROM that is the problem. If it is a model made by SAMPO check R024 2.2Mohm in the power supply. If it is a model made by Tatung check D803 in the power supply secondary for S/C. Also on this model check connector from control board to mainboard for faulty connection especially the contacts in the connector at the mainboard. Also check I801 in the power supply.

QUESTION NO. P423-6: Mag DJ800 X19001 monitor had no HV. Transistor FS10SM had open emitter, no other signs of damage in area so replaced it with an available ECG-2331 and everything works but now concerned about adequate rating. Need proper cross for transistor marked FS10SM 16A. Case is TO-3PJ.

FS10SM-16A would be a Mitsubishi N-channel MOSFET, rated 10 Amps, 800 Volts, so in actuality, it does not have an emitter, and, yes, a bipolar device like ECG2331 is indeed a bad cross. In fact, ECG2377 may not quite measure up. Try B&D Enterprises (www.bdent.com) for the original FS10SM-16A, or for a cross, you might try an STW11NB80, which is listed by Mouser (www.mouser.com), or an IRFPE50, which Digikey (www.digikey.com) is listing.

Since posting the question, I am embarrassed to report that I discovered the FS10SM-16A is an Nchannel power mosfet. The "open emitter" as measured with a meter was actually the source terminal. I re-installed the mosfet and the monitor still worked fine. The actual "fix" was probably the result of my re-flowing many of the solder joints in the HV area at the same time as I replaced the mosfet with a transistor. (The raster was slightly wider with the transistor installed so I assume the mosfet is part of a HV control circuit).

QUESTION NO. P323-4: Sceptre P773 monitor has a pincushion and width problems that cannot be adjusted.

Check the High Voltage Poly caps in flyback area for shorts or opens. (Note) These caps are fairly big in size.

QUESTION NO. P419-6: Samsung synMaster 17Glsi, after warmup the screen goes blank, indicator is green. Try to push BNC/D-sub in front panel no response. If powered off for long times, same symptom occurred.. Also I need a cross reference for Transistor IRF PC40.

IRFPC40 is an N-channel MOSFET, 600 Volt, 6.8 Amp, 150 Watt, Rds[on] < 1.2 ohm, TO247 case style. It is readily available; for example, from Digikey (www.digikey.com). A cross reference for IRFPC40 could be ST Micro's STW7NA60.

Replace 2kV caps (G2,ground) on picture tube socket.

QUESTION NO. P419-4: Acer 7154s monitor is dead with just a fast flashing green led. C335 was burned, replaced with no result.

Check FET Q317; if it has shorted, then check that L304 has not burnt/shorted, and that its inductance has not dropped below about 0.7 mH. Also check D316 and D317. Since C335 had burnt, check R214, IC201, and Q310 as well.

QUESTION NO. P418-8: Cornerstone color 21 [nec,jc-2142umw] monitor. I replaced Q581-2sc3998 and Q5g6- 2sk758. The high voltage is back but now the side pin can only be corrected a little bit.

Assuming this brand is like the NEC 6FG, try checking the pincushion daughterboard, on the left side of the main board. First check for any leaking electrolytic capacitors at this board, or where the input connectors are located. Check if +12V and -12V are present on pins SA4 and SA5 of the connector. Also check IC5S3, an LM324A-type op-amp, on the daughterboard, as this can sometimes fail.

QUESTION NO. P417-8: Seanix KM-730 monitor FCC ARFKM730 seems to be made by Sampo, has all the video crammed into the center 4 inches of the screen, the very middle is clear and an inch on either side is distorted.

I believe the horizontal yoke is driven by Q730 in FCC# ARFKM730. It sounds like Q730 is leaky or breaking down. Besides Q730, also check the Horizontal drive capacitor C757, drive transformer T703, box capacitor C761, and also check for bad solder connections on these components and the horizontal yoke connectors.

I may have not described the problem correctly, the horizontal seems fine, it fills the screen width perfectly, it is vertically where the problem is, like the vertical height is misadjusted but with distortion on both top and bottom.

QUESTION NO. P417-3: Gateway EV900-7000595 monitor is dead, will not power up, no major parts shorted in power supply or hv circuit except VR501 is fried along with R538 and R573. Also I need the value of VR501 (the ABL adjust control located at the very back of the monitor, next to the flyback) and R538 and R573.

VR501 = 20K, R573 = 68K, R538 = 1K. However, when these parts burn, it is often due to a bad FBT. Or, sometimes, a missing 12V reference can cause a power supply overvoltage situation; one cause of this can be if D315 goes open (not short).

QUESTION NO. P411-8: Goldstar StudioWorks 76i monitor. I need a datasheet, sub or source for IC 302 that has burnt, I think it is a video amplifier.

ic302 is an cva2422. I get mine from LG in OZ.

QUESTION NO. P314-7: Acer 7176i monitor. I need the values for R348, R349, R455 and the part number off D314.

R348=4.7k .5w, R349 =100k .25w, R455 =3k, D314 =rgp10d.

QUESTION NO. P411-4: IBM 2124-001 monitor. I need a value for c335, c336 and r214.

This IBM is similar to the Acer 7154e chassis. C335 = 220 pF/2KV, C336 = 0.01 uF/50V, and R214 = 15K ohms.

QUESTION NO. P410-1: Acer 54E Monitor the display goes off in about a minute of being on. Then it flashes on and off. C335 dark brown, D316 OK in circuit, Q317 shorted. Replaced & burnt in no time. OK in Circuit, L304 .8 ohms, R214 12.83Kohms, D317 OK in circuit.

If C335 and Q317 both burned again, first use a good-quality disk cap for C335, 220 pF at 3KV is recommended. Along with Q317, the D317 and L304 form a boost circuit, to raise the raw B+ (45V) going to the HOT. I do not trust ohms readings to check L304, you need an inductance value; nor is in-circuit testing D317 adequate. L304 is nominally "2 mH", but many good L304's will measure 0.8 mH on an inductance meter. However, if the inductance of L304 falls much lower than that value, the excess current will blow Q317. Ultrafast rectifier D317 must be tested for reverse leakage out-of-circuit. Replace it if any reverse leakage is observed. Although the value of R214 = 15K ohm is not truly critical, in this situation, I would replace it anyway. It seems out-of-spec; I would be concerned that it has been damaged, and that your meter's resistance reading may be quite different from its resistance value at high voltage and high frequency. If that is the case, IC201 may be damaged as well, and need replacing. Also check that the values of precision resistors R216 & R220, going to the B+ sense pin (pin 4) of IC201, are still at the correct value.

QUESTION NO. P410-2: Acer 54E Monitor has a blinking green led and a clicking noise on the board. Q310 B C E Out of Circuit + - .55, - + OL, + - .48, - + OL, + - OL, - + OL, C335 Burnt, D316 OK Out of Circuit, L304 .8 ohms, R214 Burnt, D317 OK in circuit.

Because R214 = 15K ohms is burnt, IC201 = TDA4858 probably needs replacing. Be sure to use a good-quality disk cap for C335; although 220 pF/2KV is usually installed, it is better to use a 3KV rating. Mouser Electronics (www.mouser.com) has these, in the US. Check R216, R220, off pin# 4 of IC201, for value, check D317 for leakiness, and check the inductance of L304. For that Q310, I can't tell which pins go with which ohms, but it seems appropriate, since this HOT has no internal damper.

QUESTION NO. P46-1: Commodore 64 1702 monitor FCC BR99oy1702,UL277C. I need value of R904=brown, black...., 1/2w and R908=red, red...., 1/2w located near STR3125 reg in power supply board labeled GF-1003A (2/6).

R904=12K ohm,1/4w and R908=220 ohm,1/4w.

QUESTION NO. P49-1: emc sa-770 monitor. Replaced shorted q630 irf634a with sub 2sk526 and it shorted out too when gen. signal was applied within 1/2 minute. Other parts in hor. circuit check ok. Should I put in ecg2900?

2SK526 is not quite as good as IRF634A, but whenever Q630 shorts out, you should always replace C635 and D632 (ECG576) as well, to prevent more failures. If the C635 was 22 uF/250V, EMC recommends dropping the value on the replacement to 10 uF/250V. Also check the solder on the three resistors near Q630, R66B, R66C, R66F.

QUESTION NO. P49-3: Compaq QVision 200 Monitor. When powered on the LCD displays "HIGH VOLTAGE FAIL". I have heard if I change the metal "box" containing the FBT etc. the problem will be fixed. Where can I get it? Compaq denied having the parts.

Those chassis are made by Philips/FIMI. As you learned, Compaq is a waste of time for replacements. "HV Fail" is usually a bad Flyback, sometimes the focus module, if you also see focus/brightness problems just before the "HV Fail". Try places like LJ Enterprises (www.ljent.com), or NEI (www.neiparts.com), etc. These are very pricey items, so be sure the numbers match with yours, as there are several versions. The Flyback will have a number like AT2090-XX; focus module numbers will be like 926xx.

QUESTION NO. P49-6: HP D2846 monitor, picture distortion in all modes.

If this HP is the Sony chassis, first check for marginal/bad electrolytics. If this is not the fix, try deflection processor CXA2043Q, Sony p/n# 8-752-078-48, on the D board.

QUESTION NO. P46-8: HPD2818A monitor FCC A3LCMG737, HV present, filament lights, no picture except for a little scan just visible for a split second after power on. Monitor responds to exit standby mode when connected to PC. Cannot feel any static/HV build up on screen. G1 appears to have zero volts, filament volts are a little low 5.8-9, tried up-ing this a little, no effect (except filament brightened). Yes, its a blue label Samsung w/ digital on screen menus.

First, see if you can bring back the image by raising G2 (screen) voltage. If this is all that is needed, tell the customer not to be surprised if the CRT eventually gives out; it may be marginal. If it is not low G2, check if the color guns are too high in voltage (over 100V).

Follow-up: Tried raising G2 first thing. No luck. BLUE and GREEN gun voltages are too high about 135-140V, RED looks OK at 85V.

QUESTION NO. P46-5: Dell UltraScan 1000HS, Model D1025TM monitor will no longer power up. About every 5-10 seconds it makes a high-pitched chirp. Previously the monitor would only power on and give an orange light, even with a signal connected.

First, check the following components, Q507, Q520, Q501, D503, D516, D614, C622, and IC605. If these are all OK, or if the flashing orange LED returns, suspect a bad CPU IC, IC901; it has been a common failure in this Sony chassis.