820-3437-A "possible bad CPU?"

[KC Micro Tronix]

(On a side note. "why won't my bios programmer read any of these boards?") Reads 820-4347-B just fine.

I have a 820-3437-A

board was sent to me for "no back light" after the repair shop did a sonic cleaning for water damage.
The damage areas were around the ppbus g3 hot area and some around the display parts on "top side"
I did not see any parts or trace damage beyond surface damage. I did check closely and pick at parts.

Green light
fan spin
all S0 rails are up

Current draw is low 0.250 mA (0.500-0.600 is what I normally see on these)
Back light EN signal from CPU not present.
No display or back light on the screen.

machine appears to not boot.
Could this be a CPU.

 

[2informaticos]

There could many things.
A single corroded, or knocked off resistor is enough to stop the board working.
Usually ultrasonic cleaners knock off components; especially if no sweep function used.
Also UC will not rebuild a corroded trace!

No reason to check for video, if nor even USB activity is present.

"why won't my bios programmer read any of these boards?"
Don't use MacBook charger.
Just inject external 3.3V on 3V3_SUS line of the board.