I just bought 2 non working 17" lcd's for $10. I've challenged myself to fix them. I took them apart and one main board has a number of blown caps, the other looks fine. The one with blown caps would not power up, the other powers up but no picture whatsoever from vga, hadn't tested the dvi yet.
I took the video input board from the non powering one and put it in the powering one. I now can see the BENQ at startup very dimmly, but only with the dvi input. My first thought, the backlight. So I tried the screen from the other monitor in the now working chassis (LG PHILLIPS 170E01 A5 screens in both, btw). Same deal, saw the BENQ faintly but still all black.
I plan to replace the caps on the blown board and I may need a second input, although I will test the other one now that I know you can see the BENQ from the dvi input like that.
Do you think it's likely, given what I've described, that both backlights are out? or is it more likely that there's a power supply problem on my main board, if so, can anyone suggest how to test my backlights on their own and/or how to repair the board if that's the issue. I think I may start by replacing all the caps on both boards... thoughts?
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Hi Brian..I'd start by replacing the tcon board, that generally causes issues like you're getting, it shouldn't be hard to remove however, you may need to remove the metal shield cover to get at it, be sure to order a new one by part number on the board not tv model, best place to get parts is shopjimy, stay away from ebay if possible as you may get another non working board, Hope this helps!
IR senor may not be bad. Try using a different remote (universal) and program to TV. If universal remote works and your doesn't, you may need to purchase a remote instead of IR board. If you confirmed that the IR board is bad then replacing the IR board will fix the remote issue. IR board is an easy fix. Just open the back cover out and it's located right in the middle toward the bottom of the TV.
dreaded capacitor issue. benq's were famous for it. if you are handy with disassembly and careful you can take it apart and do it yourself. look for any capacitors with rounded tops. i fixed one ... the part is only two dollars or so but it's a good feeling to know you fixed it instead of tossing it.
Try to plug into another computer and wait to see.
If it turn up to be same it somewhere defect from the main board of the lcd.
If if not the same turn up to be, you should reinstall the OS because the software is corrupted or your display card problem.
Looks like many faukty parts on the inverter board.. replacing will not be of much help as it will soon start get troublesome once again. I would suggest that replacing the LCD inverter board is a smarter solution. Hope this helps! Good Luck!
If it's a 71g and not 71g+ resolder transistors 2sc5707 on invertor board along with grey condensers and inverter transformer.This should solve the problem if it was display shutting off with power led remaining on.Otherwise check power section.
I DID REPAIR A MONITOR WITH THE SAME PROBLEM. IT TURNED OUT, THAT ONE OF THE TWO HIGH TENSION GENERATORS FOR THE 2 LIGHTTUBES WAS BURNED OUT. BY REPLACING THE POWER TRANSISTORS AND THE 3 AMP. FUSE ON THE MAINBOARD THE MONITOR IS RUNNING AGAIN VERY WELL.