820-00165 ALL_SYS_PWRGD 0V

[No-Clean]

Board had little corrosion on C2740 and C7825 other than that board is clean.

PPBUS 8.6V
PP5V_S5 5V
3V3_S5/SUS 3.3V
PLT_RESET_L 0V
ALL_SYS_PWRGD 0V I get around 3V for a few seconds after I plug the charger.

 

[2informaticos]

Which big coils get voltage?
Inspect U1950 for corrosion; remove it and resolder.
Also test desoldering Q8150.

 

[No-Clean]

U1950 was clean but replaced it regardless, also removed Q8150 after replacing U1950 and same result.

Only L7130 and L7560 get voltage.

 

[2informaticos]

"ALL_SYS_PWRGD 0V I get around 3V for a few seconds after I plug the charger."
Which other voltages (big coils) appear at same time?
Also check U1950 pins in these few seconds.

 

[No-Clean]

All big coils get voltage for about 1 second, even vcore comes up.

U1950
Pin 8 steady 3.4V
All other pins pulse for about 1 second.

 

[2informaticos]

Any pulse at PLT_RESET_L?
If not, check at CPU_VCCST_PWRGD and CPU_VR_READY.

Check all SPI Bus Termination resistors and their traces.
Inspetc J/U6100 for corrosion.

 

[No-Clean]

PLT_RESET_L 0V no pulse
CPU_VCCST_PWRGD and CPU_VR_READY both pulse around 1V

J/U6100 are both perfect.

SPI Bus Termination resistors and their traces look perfect too.

 

[2informaticos]

Heat CPU/PCH with quality flux.
Is possible to have accumulated crap underneath.

Just in case, test first starting in SMC bypass mode.

 

[No-Clean]

That did not work, but UC did the trick, thanks a lot!