820-01987 no power

[Kyle93]

This arrived with both CD3217s having burn marks on them from minor liquid on the usb-c connector. Fans were also spinning very fast at the time at only 5V but 1.5amps. No liquid damage on the board itself.

Replaced both CD3217s board now has 20v but only using 0.06 amps. No fan spin now.

U7210 and U7270 looked burnt, replaced them as well but no change.

All AWAKE and SLP2R voltages are present but cannot enter DFU mode.

PP5V_G3S is shorted but nothing gets warm on thermal cam.

PPBUS_G3H is 12.30V

Not sure where to go from here.

 

[2informaticos]

"U7210 and U7270 looked burnt"
Very likely dead CPU...

"PP5V_G3S is shorted but nothing gets warm on thermal cam"
What is the exact ohm value?

 

[Kyle93]

PP5V_G3S 5.2 ohm

 

[2informaticos]

You should get aprox 1A/5W, when injecting 5V; something should heat on the MLB.
Be sure to set PSU limit to max first.

 

[Kyle93]

u7220 showed heat when injecting voltage.

Replaced U7220. Still 0V on PP5V_G3s but now is 38ohms

 

[2informaticos]

38 ohm is still too low; compare with good board.
Dificult to find the culprit with voltage injection now.
Maybe waiting several minutes and trying to detect small difference with IR cam.