820-00281: Not turning powering up

This board came in with no sign of liquid damage but won't power up. Only things i've found so far is PP3V3_S0 reading 2.8 and the ssd chips are warm (not hot), but the red spot in the picture is ready about 104 degrees (F). So i ran the board through the ultrasonic just case there were some hidden corrosion, no change in temp or voltage reading of PP3V3_S0. With lifeboat board taken out, the ssd isn't warm anymore. PP5V_S0 is 5.1.

other measurements noticed in comparison to another board with other issues is LA640 and 650 are both reading 1.8ohm and on the another board i get 4ohms. Not sure if this means sometime

Any suggestions


Staff member
"but the red spot in the picture is ready about 104 degrees (F)"
Which picture?

GPU and CPU core rails may have small differences in resistance to ground; depending of exact chip type.
But if you have exact same chips in two boards, the readings should be very close.

What is the CPU core behaviour?
Do you note a drop to 0.6V from 1V or so?

Without J9600, 3V3_S0 still low?
Post U8295 voltages.

BTW, as you get even S0 voltages, board turns on; doesn't boot is the problem.
No activity on cpu core rails.
Without J9600, 3V3_S0 still low at 2.8

PP3V3_S0_LEFT - 0.12
PP3V3_S5 - 3.3
PM_SLP_S3_L - 3.3
P3V3S0_CAP - 1.7

Measured pin 5 of U8295 and it's shorted to ground. Searching for the source now.
Last edited:


Staff member
Remove the chip and check if short disappears.
If yes, change U8295.
If not, continue to search for the culprit.
Believe I've isolated the short to U2800. It shorts out C2975 to 78. The short is also present on L2950. With L2950 pulled, pin 1 reads 1.20ohms while pin 2 which also ties back to U2800 reads 40ohms.
Before i pull this chip, any suggestion on what stencil to get for this chip and possibly where i can get it?
Can I remove this chip/disable it and the board still run, just without J3300 and if so, do you happen to know how to disable it so it's not looked at by the system?
Last edited:


Staff member
Try to separate U2800 from the power rails where it generates short.
And check if the behavior changes.