A1466, 820-00165-A no 3.3V S0


Hello guys,

I have a board 820-00165-A with strange behavior. When connected to the charger (board on the working bench), fan immediately starts spinning at full speed.
Investigating different power rails I found out there is no PP3V3_S0 and I also found that I do have PMP_SLP_S3_BUF_L = 3.32V.
I also have P3V3S0_EN_D = 3.27V, but P3V3S0_EN is 0.27V. This means there is no enable signal to open load switch to supply 3.3V in S0.

I have tested the diode: D8184 and it seems good (diode mode on digital multimeter shows 212 when red lead is connected to anode). I have also checked capacitor C8186 to groaund (resistance and diode mode) and I have the following: 707 in diode mode and about 800 Ohms in resistance mode.

When charger is connected I have 3.27 V on R8186 pin 1, and 0.27V on pin 2 against ground.
When power is disconnected I measure 18 kOhm on this resistor R8186 (red probe on pin 1, black on pin 2) and 13.6 kOhms (red probe on pin 2), but this is not unexpected because Ithere are other components in parallel (including diode).

I really don't understand what could be the problem. If C8186 is shorted there would not be 0.27V on pin 1 against ground.
Also R8186 seems normal.

I thought, it could be some kind of partial short further on S0_EN line, but in diode mode measured on test point near NO STUFF R8070, I have 585 reading against the ground, so here is not shorted


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Holly crap Batman, after removing C8186, computer booted without any problems. It works correctly. When testing cap with digital meter on continuity it doesn't beep, but diode mode shows something like 060, which is very unusual.