LG Flatron W2361V PSU Troubleshooting

[electrophoros]

Hi everyone.

I am trying to troubleshoot this computer screen which went black and won't power on after a power surge.

I have measured the output voltages and there seems to be proper voltage pressence on the 5V outputs, there is no voltage on the 22V outputs and I am unsure of what I should be measuring on ADIM, BDIM, EN and OLP.


There also doesn't seem to be any voltage on the backpanel outputs:


I have already identified and replaced two bulging electrolytic capacitors, and there is voltage after the fuse.

I am not sure how to proceed next. Any tips appreciated.

[electrophoros]

Re: LG Flatron W2361V PSU Troubleshooting

I just noticed that my picture links don't show up. Adding them here

Pinout


LCD panel outputs


Board top view

[mikey5791]

Re: LG Flatron W2361V PSU Troubleshooting

Make sure all the diodes and transistor are in good working condition and not shorted.
Btw, did you checked the middle 8 pin chip?

[R_J]

Re: LG Flatron W2361V PSU Troubleshooting

From what I can tell, If you have the +5v you should also have the +22v, both are supplied by the same transformer, so check the connections on the transformer and D201,D205.

I would start by replacing C103, C105, they are very likely the main problem with the power supply

I would replace all the electrolytic caps except for C101, it should be ok.