820-00165 no damage pulsing

[wgaca]

No visible liquid or corrosion anywhere. Reported by the user that was working slowly and then just died

All rails pulsing.
In SMC bypass will repeatedly spin the fan for a split second every 2 seconds. Might stop after a few minutes.

No short found on any coils or big caps.

Does the CPU die on these out of nowhere?

 

[2informaticos]

VCORE pulsing?
Check PLT_RESET_L too.

 

[wgaca]

VCORE is pulsing and PLT_REST_L doesn't seem to show at all. I don't have a scope to check.

 

[2informaticos]

DC voltmeter should be good enough.
Will not catch peak pulse, but you should note 1-2V pulse.

Check for pulse at CPU_VCCST_PWRGD and CPU_VR_READY.

 

[wgaca]

both pulsing
i don't get any pulse on plt_reset_l

 

[2informaticos]

Looks like PCH issue.
Heat it, may have accumulated crap underneath, or internal problem.
1V05_SUS present?

 

[wgaca]

1v05_sus is consistently present, not pulsing.
I can try heating but it's unlikely that's crap underneath. Thanks for the help i wanted to confirm i am not going crazy today