820-4924 - Missing PM_SLP_S4_L

[SairFecht]

Board not powering following a claimed power surge. Everything above S4 that I can check exists and is in normal range, no PM_SLP_S4_L, voltage rails/readings as follows:

PPBUS_G3H - 12.56
PPBUS_S5_HS_COMPUTING - 12.56
PP3V42_G3H - 3.45
PP5V_S5 - 5.02
PP5V_S4 (and 3 and 0) - 0
PP3V3_S5 - 3.34
PP3V3_S4 (and 3 and 0) - 0
PP3V3_SUS - 3.34
RTC_RESET_L - 3.34
PCH_SRTCRST_L - 3.33
PCH_INTVRMEN - 3.23
PCH_DSWVRMEN_L - 3.23
SYSCLK_CLK32K_RTCX1 - 32khz
PM_DSW_PWRGD - 3.44
PM_BATLOW_L - 3.33
PM_RSMRST_L - 3.30

Not entirely sure where to head with this one, any suggestions?

 

[2informaticos]

Post PM_PWRBTN_L, PM_RSMRST_L and SMC_ONOFF_L levels.
Trigger SMC_ONOFF_L and check for drop pulse (3-0-3V) at PM_PWRBTN_L.
If yes, PCH issue; check 1V05_SUS presence.

Also try to start in SMC bypass mode.

 

[SairFecht]

PM_PWRBTN_L - 3.43
PM_RSMRST_L - 3.30
SMC_ONOFF_L - 3.44

PM_PWRBTN_L drops when SMC_ONOFF_L is triggered

1V05_SUS - 1.05

SMC bypass has no noticeable affect.

 

[2informaticos]

"PM_PWRBTN_L drops when SMC_ONOFF_L is triggered"
Now check if PM_SLP_S4_L pulse at same time.

An o-scope can help you to catch any fast pulse.
If no pulse (for sure), then PCH issue.
You can try heating PCH with good flux.
Just to burn eventually accumulated crap underneath it.