820-00281 No power, PCH issues

[tcampbell34]

Hello. This board has turned into a real nightmare. Originally it came in with liquid damage and minor corrosion around U7650, U3100 and U4200. Was only getting 5v and PP3V3_G3H was shorted to ground. I cleared the short by removing C3100 and got 20v but only about 30ma. Was missing PP3V3_S5 and it was not shorted, so I replaced U7650 and some components near it that were corroded and then I checked PP3V3_S5 again before powering the board and it was now shorted somehow. I went to remove U7650 again, thinking it was causing the short, and after only like 10 seconds of heating it with my hot air station, I heard a loud pop noise so I stopped heating. When I flipped the board over, I saw the PCH die actually exploded somehow and a large chunk blew off from it. Weird because I was not even heating the board in that area. I removed the damaged PCH and the PP3V3_S5 short was gone. I replaced it with a new PCH I bought on Aliexpress, but was still not turning on. I was not getting PM_SLP_SUS_L and found it was because the trace was broken. I had to run a wire under U7800 to reconnect that and now I have PM_SLP_SUS_L and all S5 voltages, but missing PM_SLP_S5_L. I have since found more broken traces on PM_PWRBTN_L and PM_DSW_PWRGD, which I ran wires to fix. I'm sure I have another broken trace somewhere but I'm not sure where to look. I checked each of the signals below and they seem normal. What else is needed for PM_SLP_S5_L?

PM_SLP_SUS_L - 3.3
PM_SLP_S5_L - 0 (Does not pulse when trigger)
PM_SLP_S4_L - 0 (Does not pulse when trigger)
PM_SLP_S3_L - 0 (Does not pulse when trigger)
PM_SLP_S0_L - 0 (Does not pulse when trigger)

PM_PWRBTN_L - 3.3 (Does drop when trigger)
PM_RSMRST_L - 3.21 (No reaction when trigger)
PM_DSW_PWRGD - 3.3
RTC_RESET_L - 3.07
PCH_SRTCRST_L - 3.07
PCH_INTRUDER_L - 2.79
PM_BATLOW_L - 3.3
S5_PWRGD - 3.29

 

[2informaticos]

Possibly liquid went inside board, between copper layers.
I suspect internal broken trace.
Can be a problem between PCH-U7800-SMC.
PCH receives the required signals to start power on sequence.

 

[tcampbell34]

Yea, this board is done for. It has a ton of broken traces. I was checking diode mode values on all the resistors on the opposite side of the board from the PCH. I found a bunch of OL values, which does not match another board I have, so these are all broken traces. Thanks anyway.