A1706 Macbook Pro PPBUS_G3H Shorts to ground when charger connected

[zeroalpha]

A1706 with some liquid damage. I've cleaned it but PPBUS_G3H will short to ground when its connected to the charger.

Watch a short clip of whats happening here:

https://youtu.be/HcegjB4fWVM

Is there a problem with PPBUS_G3H and what should I look for?

[mon2]

Re: A1706 Macbook Pro PPBUS_G3H Shorts to ground when charger connected

1) remove all power.

2) meter in resistance mode.

3) measure the resistance to ground of ppbus_g3h. What is the measurement?

4) remove all power. Remove the output fuse on ppbus_g3h.

5) measure the resistance to ground on each side of the removed fuse pcb pads. Post each measurement.

6) power up again - with the fuse removed. What is the voltage to ground of ppbus_g3h at the producer side (ISL) of this power rail ?

Often, a shorting cap will cause the fault you are observing. The resistance checks will confirm this case.

Do you have an adjustable power supply?

Can it be used to dial up a 1v0 output voltage?

[zeroalpha]

Re: A1706 Macbook Pro PPBUS_G3H Shorts to ground when charger connected

3) 2 MΩ

5) Removed F7000.

Pin 2 (PPBus_3GH) = 2 MΩ
Pin 1 (PPVBAT_3GH_CHGR_REG) = O.L

6)

Pin 2 (PPBus_3GH) = 1.1v
Pin 1 (PPVBAT_3GH_CHGR_REG) = 20v

With the fuse removed PPBus_3GH no longer goes short to ground either

Yes i have an adjustable power supply