820-00165 No power(SOLVED)

[ZAKLINTOWN]

Hi guys,
Have 820-00165 here, liquid damage while ago, machine was working fine, suddenly stopped working 2 days ago, U1900 corrosion on 2 pins, replaced, U6100 Pin 5 small corrosion, but all voltages(3.3) present at U6100, jtag removed was corroded, U7501 looks good, SMC good, small crap around PP3v42 area but all voltages present compared with working board, U1950 area clean,
PPbus 8.57V, PP3V42 3.4V, SMC_Reset_L 3.3V, PP5V_s5 5V, PP5V_S4RS3 1.18V - no short 52Kohm's, P3V3_S5_REG_L 56 ohm tp ground however while charger connected 3.3V present, other areas of the board looks good,
Any hints to go further?

 

[2informaticos]

"U6100 Pin 5 small corrosion, but all voltages(3.3) present at U6100"
And why do you think this is good???
In fact, means that PCH doesn't read/write the BIOS.
Be aware, do not make wrong assumptions!

Check all SPI Bus Series Termination resistors and their traces.
But fix the power problem first; you don't have 5V_S4.

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L.

 

[ZAKLINTOWN]

If Im trying to bypass SMC now fan spins twice with few second interval PP5V_S4RS3 goes up to 5V at that time, but no further action unless I trigger SMC_ONOFF_L pads with tweezers - fan gives little spin everytime.

 

[ZAKLINTOWN]

PMS_SLP_S4_L goes high twice with few second interval if charger reconnected and then stays on 0V

 

[2informaticos]

Check if all big coils pulse too, including VCORE.
Also check for pulse at pin 3/U1950 and PLT_RESET_L.

 

[ZAKLINTOWN]

Replaced SMC,
I got it to turn on however now ran into issue with no keyboard/trackpad, opt out keyboard/trackpad/ipd cable - tested logic board into good working housing - issue the same.

 

[2informaticos]

No TP/KB before and after logged in macOS?

 

[ZAKLINTOWN]

No at all, can not even Alt boot or PRam with internal keyboard, however SMC reset works with keyboard.

 

[2informaticos]

Check power rails at trackpad connector and post U4810 voltages.

 

[ZAKLINTOWN]

U8000 was bad - didn't get PP3v3_S4 this one solved however now missing bluetooth

 

[2informaticos]

Tried another airport card?
Check U3510 area.

 

[ZAKLINTOWN]

Yes tried other card, didn't work, was missing Pin10 compared to good board, replaced U3510 and customers wifi turned out bad as well - issue solved, thank you very much for all your input.

 

[2informaticos]

Bluetooth works now?

 

[ZAKLINTOWN]

Yes it works, no further issues found.