Help, input voltage creates PP3V42 missing (820-3787-A)!

[MellowMan]

Hullo all,

I have an A1398 15" retina (820-3787-A) and was troubleshooting and realized that R7020 was broken. I removed the resistor (which had cracked in half) and I think it took the input pad with it when I took it off. The input voltage for this resistor is supposed to be 20 V, but is only 16.5 V. It is supposed to receive the drain voltage from Q7010, an 8-pin (well 9, if you count the "Powerpak" pad underneath) DFN. Here are the diode mode measurements for the circuit (red cathode on ground, black anode on the component); I just need help interpreting them.

C7012[1]: 0.612 V
C7012[2]: 2.951 V
R7010[1]: 0.608 V
R7010[2]: 2.928 V
R7011[1]: 2.928 V
R7011[2]: 2.951 V
R7012[1]: 0.611 V
R7012[2]: 0.000 V
D7010[1]: 0.000 V
D7010[2]: Over Load V

Q7012[1]: Over Load V
Q7012[2]: Over Load V
Q7012[3]: Over Load V
Q7012[4]: Over Load V
Q7012[5]: Over Load V
Q7012[6]: Over Load V
Q7012[7]: Over Load V
Q7012[8]: Over Load V

D7105[1]: 2.325 V
D7105[2]: 2.325 V
D7105[3]: 0.556 V

R7020[1]: 2.325 V
R7020[2]: Over Load V

D7005[1]: 0.003 V
D7005[2]: 0.003 V
D7005[3]: 0.181 V

Included are the .brd and .pdf (schematic) for the 820-3787-a board. With no PP3V42_G3H, I can't boot or charge; no LED on the magsafe2 or anything either. There is some liquid damage I think, so I have to get it cleaned probably. Maybe Louis is cheap

Thanks for your time,

MellowMan

[piernov]

Re: Help, input voltage creates PP3V42 missing (820-3787-A)!

16.5V is not a problem. But make sure you're using genuine Apple Magsafe2 85W.
If R7020 burnt, maybe D7005 is bad, U7090 is bad or there's a short to ground on PP3V42_G3H.