820-00165 S0 Rails Pulsing

[brunomotter]

Got this board here which had no power. PP3V3_SUS was low, only 0.45V. I found corrosion under U8020, so I replaced it and got back PP3V3_SUS to normal. Now the board pulses all S0 rails in loop but does not turn on. I inspected whole board and could not find any more corrosion in it. Any ideas?

 

[2informaticos]

Tried in SMC bypass?

Should be good to reball SMC.

 

[brunomotter]

In SMC bypass, it does a quarter fan spin and dies. Will try reballing it

 

[brunomotter]

Rebelling the SMC did nothing different to this board. Same thing, still pulsing S0

 

[2informaticos]

CPU core coils pulsing too?
What about PLT_RESET_L?

 

[brunomotter]

CPU VCORE pulses too and also PLT_RESET_L

 

[2informaticos]

POssibly accumulated crap under PCH.
Heat it with quality flux.