Acer P205H 2 sec to black with new caps

[TimmieT]

Hello, I have a P205H that lights up then goes black after 2 seconds.
I have replaced all caps other then the 50 volt ones, and the 450v one.
The board looks like it got hot by the two big diodes, on the other side of them is two chips, both ( D545 8A7619 )>Q105, Q104. I thought they could be bad but can't find a replacement.
Any help would be great thanks.


https://drive.google.com/folderview?...1k&usp=sharing

[leggot]

Re: Acer P205H 2 sec to black with new caps

HI TimmieT,

This could be the cause of several reasons, the most likely of which -

1. It could be that one of the components is reporting a failure or a short and causing the unit to turn off, most likely the backlight inverter.

2. There could be components on the power board that is causing the board to briefly work. It is possible to diodes with the diode function on the multimeter.

I would recommend trying to turn the monitor on with the backlight unplugged from the power board and seeing if it still suffers from the same issue.

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

I forgot to mention I tested all 4 cclf with external inverter and they all work. Also I thought if you have no load on the inverter it will shut down. The inverter and power board are the same, so are you saying to try with the ccfl's unplugged?

[leggot]

Re: Acer P205H 2 sec to black with new caps

Ah, that helps. So you are saying you have tested the unit with a different powerboard/inverter and the unit correctly functions? If this is the case, it is possible to isolate the issue to be internal on the powerboard.

You also didn't mention if you were able to test the diodes on the board with the diode function on the multimeter. Another thing, I just though of is checking for bad soldering joints- just google some pictures and see if you see any.

[ReeceyBurger123]

Re: Acer P205H 2 sec to black with new caps

Hello, could you post pictures please and do you have a digital multimeter ?

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

the diodes seem to test ok they 183 one way and open the other, but it takes a second. Most other diodes on the board test 540 and open. The diodes however are not the things that I thought might be bad they are on the other side ( mossfets maybe Q104, Q105 )
Thanks again for the quick help

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

pics are on this link
https://drive.google.com/folderview?...1k&usp=sharing
Let me know if that won't work

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

So today I cleaned up a lot of spots that looked like they could be dry joints, but no go.
The screen lights up and looks great for about 2 seconds then the screen goes off and the power light stays blue.

[vinceroger69]

Re: Acer P205H 2 sec to black with new caps

whats the part number of the inverter transformer have you checked the winding resistance?

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

inverter trans 6131040002P00 lse u10a H Thats all I see on it.
To test it does it need to be removed first?

[diif]

Re: Acer P205H 2 sec to black with new caps

It looks rather brown like its got hot around that diode, maybe take it out and test it.

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

With the diodes removed they both test open one way. For the other way they test 174 and 149. Sounds ok I think???

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

It looks to me the things that got hot might be on the opposite side of the diodes. Q104, and Q105. Does anyone know what those are or how to test? Thanks

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

I found a guy on ebay selling 1 Piece AO D454 AOD454 TO252
so I looked up AOD454 on all data
AOD454 - N-Channel Enhancement Mode Field Effect Transistor
Features
VDS (V) = 40V ID = 12 A (VGS = 10V) RDS(ON) < 33 mΩ (VGS = 10V) RDS(ON) < 47 mΩ (VGS = 4.5V)


I already have a pack of C5707 NPN Transistors, does anyone know if those might work?
Thanks again for all the help

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

AOD454A
https://cdn.badcaps-static.com/pdfs/...d8ddfa4d2f.pdf
AOD454 or AOD454D
http://www.datasheet4u.com/download.php?id=564340
It looks like those are both Mosfets I think.
again thanks for the help

Also Digikey has AOD454A but not sure if that would work

[TimmieT]

Re: Acer P205H 2 sec to black with new caps

I also have some FDD8447L Mosfets but I'm not sure if they would work