820-00165 boots but no USB activity

[No-Clean]

This is a weird issue, board had corrosion around Q8131 and R8131, that all got fixed but the board still does the same: Turns on all the way for about 10 seconds, shutsdown then starts up again and stays on VCORE is 1.8v at this point, but there is no USB activity, already tried clean BIOS and reflow SMC and same thing.

 

[2informaticos]

PLT_RESET_L stays high?
Possibly corrosion underneath PCH/CPU.

 

[No-Clean]

PLT_RESET_L 0v

I just ran it thru the UC and oven to remove corrosion if any, same behavior

 

[2informaticos]

Check CPU_VR_READY and CPU_VCCST_PWRGD.

 

[No-Clean]

CPU_VR_READY 1V
CPU_VCCST_PWRGD 1V

 

[2informaticos]

PCH issue.
Possibly crap accumulated underneath.

 

[No-Clean]

Cleaned glue around CPU, put 559 flux and ran it via the ZaoMao reballing machine and same exact behavior.

 

[2informaticos]

Pin 3/U1950 is also high?

 

[No-Clean]

No, it is 0V

 

[2informaticos]

What about pins 5, 6, 7?

 

[No-Clean]

Pins 5 and 7 3.4V
Pin 6 0V

 

[2informaticos]

Sometime is a sign of SMC failure, or bad solders.
You can try soldering pins 5/6 together and check if pin 3 goes high.