820-2915 only turning on when SMC_PM_G2_EN probe point is touched

[ytesfay80]

I have this board that doesn't show any signs of liquid damage. It shows a green light on the charger when plugged in but nothing else. PPBUS_G3H is 12.59v and there was no voltage on any of the S5 or S3 rails.
I traced the issue to U7201 where there was 0v on PM_SLP_S4_L and SMC_PM_G2_EN. I went to the probe point(1227) that is next to the SMC(U4900) to measure SMC_PM_G2_EN and all of a sudden the fans spun and the CPU got warm.
I turned unplugged the charger and plugged it back in but again no fan spin. When I touched the probe point with any metal the fan starts spinning again. There is continuity from that probe point to R7940.

I haven't seen something like this before and don't know what I could do to fix this.

 

[dukefawks]

Remove R7940 and then diode mode on both pins.

 

[ytesfay80]

Before removing R7940 it shows 0.545v on both sides in diode mode.

With R7940 Pin 1 is showing 0.58v in diode mode and Pin shows 0.585v.

 

[dukefawks]

Hmm, that seems fine. I have had this issue once too and it was a ripped up pad under the SMC, but I confirmed that with diode mode. SMC is suspect now.