Macbook Air A1466 820-00165-A PP5V0_S0 missing

[Praveen Sahwal]

Hi

got an Macbook Air A1466 820-00165-A. Initially found liquid damage on U3210 and near C3286. replaced it and cleaned.
but there was still no life. i can notice a pulse when switch on the power supply. current goes to normal 350-400mAmp just for 0.5 second then goes to zero and again one more pulse after 1 -2 sec and jump upto 200mAmp. after that no activity.

I removed U8080 and notice presence of PP5V_S4RS3 which is stable at 5V. tried replacing U8080 but no change. found P5VS0_EN absent and PM_SLP_S3_L also absent.

i removed U8080 and got P5VS0_EN , PP5V_S4RS3 and PM_SLP_S3_L present. tried to trace down PP5V_S0 to find the problem but could not find any.
please suggest what could be the possible solution.

thank you

 

[2informaticos]

As usual, try first turning on in SMC bypass mode.

Remove Q8150 and test again in normal mode.

 

[Praveen Sahwal]

Tried SMC ByPass Mode.
Removed Q8150. Same Response PP5V_S0 still changing from 0 to 4.5 V.
PPBUS_G3H -8.62 stable.

 

[2informaticos]

Check for pulse at ALL_SYS_PWRGD and all big coils.
Trigger SMC_ONOFF_L and follow the reactions.

Inspect U1950 for corrosion; remove and resolder it.