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QUESTION NO. P082703-4: LG Studioworks 99T monitor, Q520 is fried. Part reads K2379, seems to be Sanyos mosfet 2SK2379. Part is impossible to get in Germany, are there any equivalent replacements? |
Although Sanyo's 2SK2379 is a logic-level gate Mosfet, in the LG 99T circuit, Q520's gate is driven by a 12 Volt source, so a standard-gate Mosfet like Fairchild's IRFS650B or SSS45N20B (or SSP45N20B with an insulator) might substitute for 2SK2379 in this location. |
QUESTION NO. P082203-3: LG Flatron 775FT monitor. I need the equivalent for FJAF6812 horizontal transistor. |
Possible substitutes for FJAF6812 include 2SC4890, 2SC5411, BU4525AX, and NTE2365 with an insulator. |
QUESTION NO. P71003-7: LG Studioworks 74m monitor, FCC BEJCM710. Initial problem was no go with ticking sound. Checked H.O.T which was ok. Replaced Flyback Transformer, and monitor now operates BUT only when the video cable is not plugged into the rear of the monitor. As soon as I plug the cable in the monitor goes into standby mode, and B+ goes high. |
Check the B+ coil and capacitors, coil is to left of fbt near p/supply inspect closely for burning and test value, check the fet also. Every now and then one of these will do more damage when the fbt goes, some only the fbt. |
QUESTION NO. P51903-5: LG studio works 775N monitor, is too dim. I checked power supply voltages they seem ok. There is no burnt resistor or blown capacitor. |
More than likely your CRT has low emission. Had a lot of these fail at the end of the 3 year warranty. LG ran out of replacement CRT's in Canada. |
QUESTION NO. P52203-2: Goldstar (LG) 1465DLs monitor FCC BEJCH480; Chassis: CA-32. R726 burned (need value for replacement), also C723 (need value and specifications) seems burned too, both related to the FB. If both would be replaced, will they burn again? |
R726 is 10K ohms, and C723 is 1 uF/63V. These were probably burned by a defective flyback, so the flyback would also need replacing, or they are liable to burn again. |
QUESTION NO. P42503-2: LG Studioworks 795SC monitor Chassis CA-55, the power supply is bad! The TOPxxx and mosfet are burned. Is there an replacement for this TOPxxx? |
IC903 is TOP223Y; an LG/Goldstar supplier may be able to provide this IC, as LG part# 0IPF223000A. L.J. Enterprises (www.ljecc.com) is also listing TOP223Y, on-line. |
QUESTION NO. P42203-2: LG 910sc monitor. I need the value of burned FET Q901. |
The LG parts list shows Q901 as 2SK2843, which is a Toshiba 600 Volt, 10 Amp, 45 Watt Mosfet. 2SK2843 is listed as LG part no. 0TF284300AA. |
QUESTION NO. P41503-9: LG Studioworks 440Si monitor. I need the value of fried R843 near flyback. |
R843 is 12K ohms; check if a defective flyback had burned R843. |
QUESTION NO. P21803-6: LG cb563g monitor. I need a sub for c5803 transistor on horizontal. I tried bu508df and there is a white band coming on the left. |
The KSC5803 is a 12 Amp HOT, and has no internal damper diode. BU508DF is only rated 8 Amps, and has a damper. To sub KSC5803, a 12 Amp HOT like 2SC4890, 2SC5048, or BU2525AF, would be more appropriate. If it is actually KSC5803D ('D' suffix), then it does have an internal damper diode, and a HOT with an internal damper, like BU2525DF, might be used. |
QUESTION NO. P62502-10: LG795SC monitor FCC BEJCB790 has shorted Q514, 515, 516, 531 & D528. Flyback checks out at 34.6KV, not sure about IC501 but has 1K. Resistor at J80 link and link where R555 (1K?) should be according to my schematics. Is this assembly incorrect or is there a mod it just means that the spark gap has no resistance from the flyback point? This is the basic version or early version to the LG made Apple Studio Display M6496 17 inch. |
That HV level is excessive; it should be about 26KV in this LG model. A bad flyback (6174Z-1024B or Y265382) can cause excess HV in this LG; the HV adjust is at VR501. |
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. 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. 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. 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. 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. P116-4: LG studioworks 44m, 14 inch color monitor is fine when switched on but after a use of app. one hour the image gets blurred and the brightness level increases considerably. All voltages at the CRT remain unaltered ie. the same as when switched on but the pin at screen grid rises from 242 volts to 310 volts positive. It seems that this problem is caused by the increase in screen focus and may be final anode voltages at the CRT. However all the SMPS voltages and the voltage at FB output transistor collector plus the control grid voltage of -100 volts remain stable. Is it the FBT that is faulty? |
With no model number provided, one cannot be specific, but certain Goldstar 14" chassis are known for getting bad FBT's with such symptoms. |
QUESTION NO. P310-3: Logix LG-143snie monitor with a faulty ic902 located on a small circuit bd used to power up the monitor when a video signal is applied. I need a replacement number for this component. Its only markings are a509 k12no 6l made by SGS Thompson Malaysia. |
That "IC" is a logic-level FET, SGS# STK12N06L. You did not say if yours is an SMD type, or a thru-hole FET (it comes both ways). If you cannot find it, I suggest getting one of SGS's STD12N06L-1 (thru-hole), or STD12N06L (SMD), for example, from Mouser (800-346-6873, cat# 511-STD12N06L1 or 511-STD12N06L). If it is the thru-hole FET, it would be good to attach a small heatsink, if there is not one present already. These STD FET's are similar to the STK type, but the packaging is a bit different. |
QUESTION NO. 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. 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. 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. |
QESTION 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 above50kohm & 2nd s.w VR'S. |
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 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. 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. 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. P721-2: Necesito Remplazo del Transistor A1837para Monitor Goldstar. |
A1837 = Transistor 2SA1837, Mouser Electronics (800-346-6873; www.mouser.com; e-mail sales@mouser.com; FAX 817-483-6899, referencia 620-2SA1837); y B&D Enterprises (800-458-6053; www.bdent.com), y MCM Electronics (800-543-4330; www.mcmelectronics.com). |
QUESTION NO. P66-1: Goldstar 1453AUTO monitor. I need to identify IC 601 and HOT (Q706). |
If Chassis CA-19, Q706 - 2SC4744, IC601 - TDA1675A. |
QUESTION NO. P810-2: Laser SVGA 14" monitor (Goldstar CA-14 chassis) with a horizontal line (no vertical deflection). I changed vertical IC TDA1675 to EGC1862, no change. |
If there is still no vertical deflection after replacing the vertical deflection IC, start troubleshooting around this chip you should be able to trace from it to the problem. Are both the IC's power supplies (for the amp, and the output) present? Are any associated components bad? Is there a vertical input? Is there a short, or an open/bad connection or component, off the output or in the vertical yoke circuitry? Is there a high output at pin#13 that might indicate a bad yoke circuit? Get the datasheet for the TDA1675A IC from www.st.com/stonline/books/pdf/docs/1192.pdf The circuit diagrams and pinout should be a help in doing this troublehooting. |
QUESTION NO. P715-10: Goldstar 1727 monitor, CA-27 chassis. Need the value of R448 that has burnt. |
R448 = 390 ohm. Resolder the connections on Q405, that's probably why it burned. |
QUESTION NO. P61-5: Goldstar CMT-4568 Chassis NC-06X1 No verticle deflection. Output from IC02 pin 6 is flat +5v DC. Is the problem likely to be with IC02? If so, can you assist with e replacement cross-reference. The chip is labeled NEC D6104C. |
The full number for this NEC chip is UPD6104C. Try Union Electronic Distributor, Illinois (800-648-6657) or MCM Electronics, Ohio (800-543-4330) for this IC, both had listed it in their stocks. |
QUESTION NO. P116-10: Goldstar GHV-1280M VCR. Need voltage regulator information, ie part number, replacement type, etc. The suspect IC is D101. The power supply works in European voltage, but not 110 vac. All voltages are low, and I believe the regulator cannot handle it. |
European Voltage? 220, 208, or what? That unit may be set for 220 input. Plugging into 110 will cause all voltages to read low and may cause some items to overheat. Findout what you are working on, get the proper matching transformer for the AC supply, then troubleshoot. |