820-00840 20V, 0A - PMIC?

[baker_jeff]

Liquid damage with slight corrosion around U2890, U3500, Q7660. So slight that I thought brushing it off with alcohol would be enough to bring it back to life. Rest of the board looks mint.

No traces or pads corroded but I did replaced U2890, U3500, Q7660, Q7680 asa precaution with no change.

Taking 20V @ 0A. Cant see any shorts around U7650.

U7650 voltages are as follows:

Pin 1: 0V
Pin 2 (PP5V_S4): 0V
Pin 3: 0V
Pin 4 (P5VS4_EN): 0V
Pin 12 (P5VXX_EN): 0V
Pin 20 (S5_PWRGD): 0V
Pin 21 (P3V3S5_EN): 0V
Pin 29 (P5V5_S5): 0V

Diode mode and resistance to ground:
L7670: 0.407V 900 Ω
L7690: 0.353V 780 Ω

Diode mode at 5V_S5 is 0.410V

PP3V1_RTC: 3.1V
PP3V3_LDO3V: 3.3V
PP1V25_VREF: 1.23V
PMIC_SHUTDOWN_L: 0V
SMC_ONOFF_L: 3.4V

On this board, R7828 is the one present and reads 100kΩ

PMIC issue??? Any help would be appreciated. Thanks in advance

 

[2informaticos]

Exact PPBUS_G3H voltage?

Check diode mode to ground at PMIC_SHUTDOWN_L.
If low, change U7800.
You can solder 10-47K in place of R7828, without problems.

 

[baker_jeff]

PPBUS_G3H: 13.04V

0.462V in diode mode on PMIC_SHUTDOWN_L

R7828 reads 100kΩ, still swap this out for a 10-47k?

Thanks

 

[2informaticos]

Yes, try forcing the signal.
If still low, bad PMIC...

 

[baker_jeff]

Awesome. Will try this shortly and report back. thanks again

 

[baker_jeff]

Even with forcing the signal with 10k resistor (PMIC_SHUTDOWN_L = 3.3V), No PP5V_S5 or anything around U7650. Guess i need to get a PMIC stencil...

 

[baker_jeff]

Swapped the PMIC (twice, from 2 different donors) and no change either time. Starting to lose hope with this one.

 

[2informaticos]

PMIC_SHUTDOWN_L stays high now?

 

[baker_jeff]

I didn'd replace the resistor back to original (still the 10k I put in there). I will swap it out and report back.

 

[baker_jeff]

noticed a short on s5 with new PCIM, fixed the short, plugged in charger, and PCH released smoke. Thanks for your help and optimism.