820-2879 turns on and off, no chime, no image on screen.

george-a

Member
Hi guys,

a new pearl came in today, and I say that not because I hate faulty motherboards (dont love them either) but because there are signs that someone already messed with the BIOS chip.

the behavior is that you press the power button, it turns on, then does one of two things:

either

(a) fan stays on and a few seconds later revs up but the is no image or what so ever

or

(b) fan starts and then stops for a few milliseconds and starts again (the light at the front goes off and then on, too)

To save time I removed the BIOS chip (thinking that it could be fucked from the previous guy) and instead of re-programming it I swapped it with one from a donor board (exact model).

I then measured most voltage rails - especially the important ones and they look ok, plus the clock signals are there.

I noticed that without the battery the PPVBAT_G3H_CONN goes to 12V and starts falling and then back again, while the gate voltage of Q7055 goes from 5 to 12 to 5 and so on (maybe this is normal when the battery is not connected??)...


No signs of corrosion, CPU and MCP get hot. No signal on external monitor.


so is it west, east? north?? south maybe... any help is greatly appreciated.

george
 

george-a

Member
I will measure asap, but the CPU definitely gets hot so I assume (assumption is the mother of all fuck-ups) Vcore is present...
 
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