A1708 820-00840 20v 0a

[sewsulle]

Good Afternoon,
This is my first post here so I apologize if I miss something.

I'm working on an A1708 that draws 20v and 0a with the board removed.
When installed in the machine, it takes 20v and 0.1a. The fan spins up and the trackpad clicks.

Some measurements:
PPBUS_G3H: 13.13v
PP3V3_S5: 3.3v
PP5V_S4: 5.1v
PP3V3_S0: 0.6v

Any help would be appreciated. Let me know if more measurements would help.
Thanks in advance

[mon2]

Welcome.

PP3V3_S0: 0.6v

Remove all power -> meter in resistance mode -> measure the resistance to ground of:

PP3V3_S0

Post your measurement in ohms.

[sewsulle]

Thanks for the reply. I apologize for the late response.

I'm reading 17.8 k ohms on PP3v3_S0 or 0.376 in diode mode

[mon2]

This rail is not shorted.

Carefully measure the voltage to ground for the following related signals:

PP3V3_S5_S0R ; near U8220
PM_EN_P3V3S0 ; neat U8220 - this is the enable signal for this PM_EN_P3V3S0 power rail

Suspecting that with the partial voltage present on PM_EN_P3V3S0, that U8220 is being enabled but this load switch is defective. Post each measurement.

[sewsulle]

I have 3.3v on both:
PP3V3_S5_S0R: 3.3v
PM_EN_P3V3S0: 3.3v

I noticed U8220 is missing! I'll take one from a donor board and see if that solves the issue. I don't see any other signs that the board has been messed with.

[sewsulle]

Replacing the missing U8220 fixed the issue and it's working perfectly.

Thank you so much!

If you don't mind, I was wondering if you would help with an A2442 that takes 5v and 0a

This was my personal laptop and I had closed it at the end of a class and opened it in the next class when it just didn't wake up from sleep (The battery was charged). I connected a charger later that night and it booted right up but touch ID stopped working. The next day it did the same thing but never turned back on when I plugged in a charger.

I though the touch ID issue was weird but I'm not sure if that info helps.

When this happened months ago I tried to diagnose the issue and suspected U5200 but there is no visible damage.

I'm not sure where to start with this one and any help would be appreciated. Also let me know if I should just make a separate post, this is my first time asking for help on here.

[mon2]

Good.

Yes, it will be cleaner to start a new thread.