820-00165 "bouncing" strange one (pristine condition no water damage)

[KC Micro Tronix]

I get a quick bounce about every 3 seconds.
rails are good
no shorts on cpu/pch
charge resistors are good.


I do get a cpu_vcore good signal.

Using the scope I do see data activity on bios but it's very brief and not normal.
it starts the read but does not pull full blocks. I have no problems reading the rom using my programmer


PCH?

 

[2informaticos]

PLT_RESET_L pulsing too?
Did you try SMC bypass?