820-3332 power rails cycling

[grmacs]

Testing on the bench with nothing connected to the board but power. Can see a slight twitch on the fans at times. Was able to verify that all major power rails are pulsing but present at correct values and PLT_Reset)_L pulses also.

Resoldered U8900 just in case. Tried new BIOS and CLeanME with no change. Liquid indicator was triggered on battery connector but board looks good - a little noticeable residue near the keyboard connector. SMC bypass gets a bit of fan spin but no start.

Thinking maybe GPU bypass, Flux and heat CPU or USC the board... Other thoughts?

 

[2informaticos]

Check if board turns on lifting all GPU coils.
You can also start removing ALL_SYS_PWRGD resistors, one by one; keep in place R7967.
Just in case, remove Q7950 first.

 

[grmacs]

I had tried the other all_sys resistors already but forgot about q7950. No luck with any of those or pulling the GPU coils.

I'm going to give it a bath and pray.

 

[grmacs]

This can be marked as solved. USC didn't change anything but being LI were triggered on battery, and my Medusa was unable to program the chip on board, I checked the SPIROM traces and discovered a missing connection from R5121 to U6100. Board now boots so should be good to go.