820-2915-b , pp3v3_s4 low voltage, no trackpad no keyboard error booting

[Nick]

hi, i got a 820-2915-b with a recently replaced gpu. the machine works fine but had previous light water damage on keyboard. replaced it but still no keyboard or trackpad,

pp3v3_s4 is at 1.78v

with or without trackpad/keyboard connected , measure 1.98Kohm to ground. what could cause this and how to solve it?

(cannot locate q7800 on the board as there is nothing where the boardview says it should be)

 

[Nick]

embarassing. didn't see it was ALLL no stuff. solved the line replacing R7803, still no keyboard, no onoff button and the os gives a "unable to verify this machine" when i try to install it

 

[Nick]

The operation could not be completed Nsurlerrordomain error - 1012

 

[Nick]

Solved the OS problem flashing a new efi. Still no keyboard

 

[2informaticos]

Trackpad also still not working?
Power button has direct connection from keyboard to MLB.
Doesn't pass through any strange circuitry...
Remove keyboard an see if board turns on/off touching SMC_ONOFF_L to ground.
Also check this signal level, does it go low with keyboard connected?

 

[Nick]

solved. replacement keyboard was defective. machine works perfectly, you can close, thank you