820-00840 pulsing rails 20v at 0amps


820-00840 came in water damages near the wifi module, had a short on C3700 PP3V3_S4_WLS and some traces near C3820 were gone, all that got repaired and cleaned up.

ppbus is 13v
PP5V_S5 pulses from 5v to 3v to 2v very fast
P5VS4_EN 0v
PPBUS_G3H_P3V3S5 13v
P5VP3V3_VREG3 3.2v


Super Moderator
Staff member
This could be many things. Given it's history, check all rails for shorts. If you have a short down stream, this will happen.


Staff member
5V_S5 goes to many chips.
I will start checking U8205/80, which both work on S5 state.
S5_PWRGD should appear before any XVS4_EN signal is enabled.


Thank you both, I learned a lot on this one, there is a short on PP3V3_S5G, I injected 1v to it and the CPU heats up, nothing else, just to check I also removed U8205 and U6100 in false hopes it would not be the CPU, but same thing, CPU heats up, any hope?