820-4924-A Water Damage, no keyboard, no trackpad

[MaxFix]

Hi,

Coffee spilled on keyboard.
No corrosion on the motherboard.
Tested with new keyboard - working.
After installation not working.
Tested with new keyboard - working.
After installation not working.
Test more times: sometimes working, sometimes not working.
Tested with good trackpad and flex. Same: sometimes both trackpad and keyboard work, sometimes only trackpad and part of keyboard, sometimes nothing at all.
Tested keyboard and trackpad pins again good working motherboard and found that pin 48 of J4802 has 0V instead of 3V.
Cleaned in ultrasonic machine - same.
Please advice how to proceed.

Thanks!

 

[2informaticos]

Find "TPAD SPI WITH SRC TERMINATION" in pdf and check corresponding resistors.
Some corrosion should affect TP/KB areas on the MLB.
Is also possible to have problems with TP cable; crappy chinese cables already reported on the forum.
Inspect the connectors too.
Possibly corroded resistors around U4910 too.

 

[MaxFix]

Checked the resistors from "TPAD SPI WITH SRC TERMINATION" - all fine.
Hooked up 3rd keyboard - works again. Installed still works. Fingures crossed it will keep that way. Maybe just a shitty batch of keyboards from China (though i try to stick to my reliable supplier).
Thanks for your help!