A1502 820-3476 no SMC_S4_WAKESRC_EN

[vincelx]

Hi,
This board has slight water damages. No fan spin.
When I power on, I got:
PM_SLP_S4_L
PM_SLP_S5_L
PM_SLP_S3_L
ALL_SYS_PWRGD
all go to 3.3V, then back to 0V after 1s
PP5V_S5=5V
PP3V3_S5=3.3V
SMC_S4_WAKESRC_EN remains at 0V.
With SMC bypass, fan spins full speed.
Can you help on troubleshooting SMC_S4_WAKESRC_EN missing?

[mon2]

What is the voltage to ground of PPBUS_G3H @ fuse F7140 ? (check both sides of this fuse).

Is it a stable voltage or does it power cycle after a few seconds?

[reformatt]

Check for presence of PP3V3_S5_AVREF_SMC and PP1V2_S5_SMC_VDDC around the SMC.

[vincelx]

PPBUS_G3H is 12.6V on both sides of F7140, stable, no pulses
PP1V2_S5_SMC_VDDC =1.2V
PP3V3_S5_AVREF_SMC =0.2V... indeed there is corrosion under U5110; replaced it, now it chimes and blink folder. Thanks a lot for this so fast pinpointing!