Acer P205H frelled

[Behemot]

I got this display with bad AOP607 which I acquired after more than 3 months (don't ask). So I placed the new one in, connected everything…and blue LED blinking! Damn it. It is strange because when I only leave the power board, runs OK. When I plug in the signal board, voltage on +22 V oscillates (that is strange as only +5 V is connected to signal board). This is still with no CCFl connected to it.

Than suddenly, without signal board connected, smoke came out of the AOP607! So I guess there is problem in the inverter area because only thign which may affect it is inverter on/off and brightness setting. So driving circuit? Or bad transformer?

This one has only 2 CCFLs and different board, 6832211000P01 with single small one-secondary transformer. Image of the board from aliexpress attached. I can get the the whole board for 14 bucks, do you think it is worth it? I got many such boards bad from there…

[Th3_uN1Qu3]

Re: Acer P205H frelled

Replace all secondary side capacitors.

[Behemot]

Re: Acer P205H frelled

I have in plan to replace them for sure…as soon as I repair it. Everything measures fine there.

[ben7]

Re: Acer P205H frelled

My guess is that the logic board draws just enough extra power to cause the PSU to start going into overcurrent protection. The display inverter could have been faulty, pushing it right to the edge.

Check for faulty inverter transformer windings, and possibly faulty snubber circuits on the inverter.

[Behemot]

Re: Acer P205H frelled

Yeah but strange is the signal board only draws directly from +5 V which is fine. The other rail is there completelly for inverter only.

The transformer secondary measures aprox. 400 ohm, not sure it that's OK. It is somewhat lower than I am used to, on the other hand, there is higher inverter voltage (transformer primary) so it needs less turns on secondary to get those 700 volts or so.