820-01700 Liquid damaged, no power

[tcampbell34]

Hello. I have a 820-01700 board that had minor corrosion on a bunch of areas of the board, mostly on the back side around the edges. I cleaned the corroded areas and replaced a few resistors and caps along the way. PPBUS_G3H was shorted to ground and I found the short was caused by either C6452 or C6466. I replaced both of these caps and the short was gone. When I plugged in the charger, it takes 20v 0.06amps and does not turn on. I had steady 12.6v on PPBUS now and all voltages up until PP3V3_S5, which was missing. I attempted a DFU restore and it completed successfully, without error and now I am getting all voltages except for CPU vcore it seems. When I plug it in now, it goes up to about 400ma before going back down to 80ma. PVCCIO_PGOOD and ALL_SYS_PWRGD are both fluctuating between 1.3v and 1.5v, which I now is a little low. I assume that means there may be an issue with U7800, but wanted to get a second opinion.

 

[2informaticos]

ALL_SYS_PWRGD is pulled up to 1V8_S5.
Check if that power rail is stable.

 

[tcampbell34]

I think PP1V8_S5 was 1.8v stable but now the board decided to commit suicide overnight. I came back to it this morning and it was giving me 20v 300ma and the right side of the board was getting hot. Now both PP1V8_SSD0 and PP0V9_SSD0 are shorted to ground, even after removing U9500, so I believe the SSD is shorted. Really weird because there was no corrosion in this area.