A1708 missing PPBUS_G3H

[nassih]

hello! I want to open a new topic about MacBook Pro a1708 820-00840 no power giving me some issues.missing PPBUS_G3H
state before replacing some components:c7078,c7062 was shorted,u6990,d6905
all this line are not present: USB meter show 5.2v 0amp
PPVIN_G3H_P3V3G3H : 0.23
PM_EN_P3V3_G3H_R : 0.12v
PP3V3_G3H : 0.2
PPBUS_G3H : 0.02
NOW i have : USB meter show 20.1v 0.08amp
PPVIN_G3H_P3V3G3H : 19.75v
PM_EN_P3V3_G3H_R : 5v
PP3V3_G3H : 3.4v
PPBUS_G3H : 0.132v

 

[real_mon2]

Remove all power. Meter in resistance mode.

Measure the resistance to ground of PPBUS_G3H. What is the measurement? If the resistance is low, the ISL buck boost regulator will sense that the current draw is too high and respectively shutdown or chirp mode this power rail.

Remove the fuse @ F7000 and power up again. What is the voltage to ground of PPBUS_G3H @ F7000, pad #1 ? Do you have a normal PPBUS_G3H power rail without the fuse?

Next, review the voltage to ground of each pin on the dual common cathode diode @ D6905. Measure and post each reading.

What is the voltage to ground of PP3V3_G3H @ L6995 ?

New to this forum but active on badcaps. We have a very active forum on low level technical support to repair such logic boards.