820-00840 water damage

[yobad]

usb c meter 20v0, 0.03a
PPDCIN_G3H 20v
PPBUS_G3H 13.6v, is low
R7020 13.6v
voltage at L7030 11v
i replaced u7000, but no change PPBUS_G3H is low

 

[2informaticos]

"PPBUS_G3H 13.6v, is low"
Why do you think that???

"PPDCIN_G3H 20v
-----------
R7020 13.6v""
Really impossible, believe me; check schematic.

Plerase, post accurate information, if you need help.

Any voltage at L7670/90?

 

[yobad]

I thought PPBUS_G3H need not be 20v, but I was wrong.
PPBUS_G3H 13.05v
L7670 3.3V
L7690 3.3V
I was wrong in the diagnostic from the beginning.

The board get into S0 state, but no Vcore.
The CPU get hot and the fan spin after while.

??????There been water damage on next backlight circuit, I know it make a risk for the CPU... Also the water damage was everywhere...


????

 

[2informaticos]

"L7670 3.3V"
Don't you mean 5V there???

Do you get voltage at L7370 and L7210/20?

Water close to backlight circuit is the worst repair scenario.
You can have now a dead CPU...

 

[yobad]

The board is consuming 20v/0.14a
L7670 5.1V
L7370 1.04V
L7210 0V
L7220 0V

There was no a lot of corrosion on the backlight circuit, I hope CPU fine. I send a photo of this area

 

[yobad]

Here is a picture...

 

[2informaticos]

Try known good BIOS, just in case.
Liquid could affect internal copper layers, where are many data signal lines.
Test the board alone on the desk, no device connected.
Just check for voltage at L7210/20.