820-00840 Got 20V Back, Still No Power

[brunomotter]

Got this board here which was previously poked by another assistance. It got liquid damage(was cleaned before) and had no 20V. Replaced U3100 and SMC and got 20V back, but still no power. Compared side by side with another board from same model and cannot find any missing components. It does not pull any current from wall charger. Could not find any shorts to GND. PPBUS_G3H stable 13V, board does not pass S5, stuck in S5.

 

[2informaticos]

Check PCH's RTC signals.
Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L.

 

[brunomotter]

PP3V1_RTC - 3.1V
PCH_SRTCRST_L - 3.1V
PPDCPRTC_PCH - 1.1V
RTC_RESET_L - 3.1V

For SMC_ONOFF_L I don't know if I understood well, but I tried to short it to and while measuring PM_PWRBTN_L signal and PM_PWRBTN_L did not get any pulses... It's steady 3.3V

 

[2informaticos]

You must make temporary short, like pressing power button.
And check PM_PWRBTN_L reaction at the same time!
Do not keep SMC_ONOFF_L tied to ground.

What about PCH_INTRUDER_L?

 

[brunomotter]

Was what I did. I shorted SMC_ONOFF_L to GND with the tips of tweezers while measuring PM_PWRBTN_L and it didn't chance. Will check PCH_INTRUDER_L

 

[brunomotter]

PCH_INTRUDER_L - 2.825V

 

[2informaticos]

Solder an wire on SMC_ONOFF_L and tocuh any metal plate when you want to trigger it; more easy than using tweezer.

You may need to reball U7800 too.
Did you take SMC from the same board model?

 

[brunomotter]

Yes, SMC is from same model. Will recall U7800 tomorrow and post results.

 

[brunomotter]

First I tried replacing the PMIC and I lost PP3V3_S5 line. Then I reballed original chip and put it back. Got back 3v3_S5 but still no power draw

 

[2informaticos]

Check PM_BATLOW_L.
Do you have correct/original charger for this machine?

 

[brunomotter]

I tried replacing SMC again, took it from a donor board where I know SMC is working(the one I was trying to fix some days ago which got dead CPU), now I don't have 20V anymore. And yes, original 96W Apple charger with original cable. Will try putting back the other SMC again and check PM_BATLOW_L

 

[brunomotter]

PM_BATLOW_L - 3.3V

 

[2informaticos]

Do you get 3V3_S5G?

 

[brunomotter]

3V3_S5G - this is strange! 1.35V

 

[2informaticos]

Diode mode to ground there?
Check PM_EN_P3V3S5G presence.

 

[brunomotter]

Diode mode to GND on 3V3_S5G - 0.322

No enable signal. Also, PMIC_PGE signal is missing.

 

[2informaticos]

PM_PWRBTN_L is controlled by SMC, but PCH can block it, if has an internal problem.

S5_PWRGD goes high?

 

[brunomotter]

S5_PWRGD - 3.3V

 

[2informaticos]

Looks like PCH problem...