820-00165 (not reading BIOS) Deep Tracks, Forgotten boards from the past!

[KC Micro Tronix]

Deep Tracks for LB repair. I am digging into the forgotten boards from the past that I could not figure out and seeing if I can fix any of them.
This one helped me learn how the BIOS and PCH works. What I do know.

The PCH is getting a good clock signal
The PCH is not stuck in a RESET_L state
The PCH is not sending the SPI_CLK_R signal and as a result is not reading the BIOS chip.
The PCH is getting the PM_PCH_PWROK signal from the SMC.
All the voltages appear normal.

So this one looks like the PCH.
Anyone have a second opinion before i donate this LB to the rework machine pile?

 

[2informaticos]

You must be sure about U6100/01 and J6100.
Check traces continuity and all SPI Bus Termination resistors; there are more than 20 resistors.

Compare diode mode readings on these lines with working board.
Don't fotget to check SMC/CPU_PECI lines.

Heat PCH with quality flux; just in case of accumulated crap between its balls.
Small leakage can compromise the communication.

Check against working board when exactly SPI_CLK_R signal is activated.

Be aware, a simple corroded/broken resistor somewhere on the PCH/CPU area can block the board.

 

[KC Micro Tronix]

Good advice. Will double check.