Macbook A2338 5V .400 Amps

[Instafixx]

Device came in as not turning on but i plugged in the charger it turned on. Worked for a day and then will not turn on.
I take out the board. Corossion on and near the Wifi chip - but no shorts. Replaced the Caps.
PPBUS_AON is 8V. Removed the Fuse - get 12.3V at C5250.
PP3v8_AON is 3.8V.

Since PPBUS_AON isnt present PP3v3_s2 is also not being generated as VIN of UC710 is absent.

 

[2informaticos]

What is diode mode at PPBUS_AON and 3V8_AON?

 

[Instafixx]

RN420/3 heating up. No shorts.
Removed them and now U7700 heats up.

 

[2informaticos]

RN420-3 shouldn't heat up.
These are discharge resistors for 2V5_AWAKE_NAND power rail.
Q420 may be shorted, or it receives incorrect enable signal.