820-2936 no USB activity

[No-Clean]

Clean board.

All test done on bench outside MacBook casing.

I get PPVCCSA_S0_CPU at 0.9V but there is no USB activity.

Already tried known good clean ME bios and same problem.

Also tried different RAM.

Any pointers will be greatly appreciated.

 

[2informaticos]

VCORE should drop to approx 0.75V, when the board boots.
Did you try different RAM?
Should be good to use DDR3 test card also.

What the client said about fault appareance?
PLT_RESET_L comes high?

 

[No-Clean]

Already had tried different RAM, but just now also tried some other one and same thing.
Client said that USB ports started failing then later on did not start.

PLT_RESET_L 3.3V

 

[2informaticos]

Check diode mode to ground on USB data lines.
Maybe PCH got damaged by some external device.