820-2936 missing PM_SLP_S4_L - waterdamage

[Fizzl92]

Hello,

this 820-2936 had waterdamage. Missing trace near Q5300, waterdamage by Q3880, SMC (reflowed), Q5030, the usually... I fixed everything visible but its not creating PM_SLP_S4_L. Just to be sure id like to get help with it so i dont miss/forget anything.

 

[2informaticos]

Did you check any voltage/signal prior to PM_SLP_S4_L in power on sequence?
Let us know which...

 

[Fizzl92]

Yes, sorry. I skipped mentioning this. Every rail above 5V_S3 is there, i could not find shorts on any rail on the board and SLP_S4_L is missing causing 5V_S3 and all rails below to be missing too.

 

[2informaticos]

Trigger SMC_ONOFF_L and check for drop signal at PM_PWRBTN_L.
If detected, chek for pulse at PM_SLP_S4_L (at same time).

 

[Fizzl92]

If i sohrt pads of R5016 PM_PWRBTN_L falls from 3,3 to 0V. But i could never observe any kind of pulse on PM_SLP_S4_L on ym scope if i shorted those pads.

 

[2informaticos]

I was expected a list with the signals you've checked.
No other way to know if you forgot something.

3V3_SUS, 1V05_SUS, PM_DSW_PWRGD, SMC_ADAPTER_EN, PM_BATLOW_L, PCH_DSWVRMEN, PM_RSMRST_L and the 4 PCH's RTC (DC) signals.

 

[Fizzl92]

3V3_SUS = 3,313V
1V05_SUS = 1,047V
PM_DSW_PWRGD = 3,491V
SMC_ADAPTER_EN = 3,477V
PM_BATLOW_L = 3,309V
PCH_DSWVRMEN = 3,190V
PM_RSMRST_L = 3,280V
RTC_RESET_L = 3,308V
PCH_SRTCRST_L = 3,308V
PCH_INTRUDER_L = 2,860V
PCH_INTVRMEN_L = 3,205V

 

[2informaticos]

Seems to have a PCH related problem.
Try heating it with quality flux.
No need to melt its balls; just burn eventually accumulated crap underneath.

 

[Fizzl92]

OK, thank you. Ill give it a try.