820-00281 no power

[Kyle93]

Arrived with no liquid damage with PPBUS_G3H shorted. U1100 was shorted. Replaced U1100, PPBUS_G3H was no longer shorted and had boot current over 2 amps for a few seconds before C8010 burned and smoked. Replaced but now board is at 20v 0 amp draw. PPBUS_G3H was shorted again from shorted u7900. Replaced U7900 PPBUS short gone again but still 20v 0 amps. ALL_SYS_PWRGD and PM_RSMRST_L 0V. SMC_PM_G2_EN 3.3V so replaced U7800 but no change

Already cleaned ME region from PCH replacement.

What should be checked next?

 

[2informaticos]

U1100 is not directly connected to PPBUS_G3H: impossible to generate short there.

C8010 got burnt because overvoltage through U7900.
Very likely CPU, or PCH is dead now; more sensitive than C8010.

 

[Kyle93]

When injecting voltage to find PPBUS_G3H short only U1100 showed heat on thermal cam. Once it was removed PPBUS short was gone

 

[Kyle93]

I made a error in my post. U8000 was faulty and replaced. U7900 was never faulty or replaced.

 

[2informaticos]

You've injected voltage into PPBUS_G3H with U8000 shorted on high-side; is the only way to heat U1100.
Big error, we explained many times what to check first, before injecting voltage.

Of course short went off removing PCH, but applying power to the board with shorted U8000 killed PCH again.