[SOLVED]820-3330 intermittent start 1/4 fan spin

[Gurmon]

Okay, i'm stuck on this one. There is no liquid spill, board is clean.

Board will start up totally fine sometimes, and then cut out into a 1/4 fan spin issue.

PPBUS-G3H is bouncing on the scope, as well as PPDCIN-G3H,

SMC_PM_G2_EN is also cycling.

I have replaced all current sense resisters, even though they where okay. U7000, and the SMC.

Its like the board has a short somewhere, but I cant find it.

Any clues ?

 

[Gurmon]

Please mark as solved, this was fixed by replacing C8371,C8340 & C8390.

I've spent too much time on this board.

 

[larossmann]

Were they corroded looking, smell bad, physically damaged or what?

 

[Gurmon]

The tants looked ok, I only replaced as I was out of ideas, so started lightly heating some parts of the board to see if the short would go away. it would go away when i placed heat at C8340 & C8390. Replaced those.
Looking directly on the other side of the board, GND side of C8371 was oxidized.