820-01700 16" A2141 does not start up

[sekidata]

This MacBook originally showed a short on PPBUS, which I traced to one of the CPU power drivers (U7410). Replacing it removed the short.
Now the trackpad clicks and the fans are spinning, but it doesn't start up. PPBUS is 12.57V and the USB-C meter reads 20V and 2-3A (without a battery connected). I have the CPU/GPU power rails and the heat sink definitely gets hot. No shorts on the big coils and the PMU outputs are good and stable. What am I missing?

 

[2informaticos]

USB activity, external video, Caps Lock LED reaction?
What is CPU core voltage after 10-15s?

 

[sekidata]

I get one brief flash on my USB mouse, then nothing. No external video. No Caps Lock light.
PPVCC_S0_CPU is initially 0.97V, then stabilizing at 0.87V.

 

[2informaticos]

CPU core usually drops to 0.65V aprox, when board boots.
Not sure exact behavior for this model.

Probably bad CPU, as it was overvolted through U7410.

 

[sekidata]

Yeah, thanks for confirming my suspicions. The CPU does get unusually hot within seconds.