820-2936-A quarter fan spin No liquid damage.

[ALB-Repairs]

Quick update.

You all probably think my methodology is ass backwards. Ive narrowed it down to V-Core related issues or potentaily a bad cpu or PCH.

Ive done this by breaking a S0 rail so V-core is not enabled. The symtoms changed, the fan remains spinning, and there is no funny business around the SMC anymore. It just acts like a board stuck in S0 now.

To further this i put the component back to re-enable ALL_SYS_PWRGD and removed U7400 and its associated V-core mosfets. Now the CPU V-core regulator is not present the board again simply acts like a board with no V-Core.

So thats managed to narrow it down with it likely being a bad CPU

 

[ALB-Repairs]

I dont believe it! What a strange set of symptoms for the issue. I replaced the U7400 IC and the thing sprung back to life! thats made my day

 

[dukefawks]

No way U7400 just fails. Probably heated something up or it was liquid damage in U7400 area. This board has a high chance of failing again I'm afraid.

 

[ALB-Repairs]

Still running beautifully. The effectiveness off heat on ceramic surface mounted caps is short lived, so i feel like i can rule that out. The only other possibility is failing alu-electrolytic's for the V-core. I will update people if it comes back to me.