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Macbook A2338 5V .400 Amps

Instafixx

Instafixx

Active member
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

2informaticos

Administrator
Staff member
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.
 
Instafixx

Instafixx

Active member
Q420 lines arent shorted.
PP2v5_AWAKE_NAND is 3.4V

Has an exact same issue before. Had replaced U7700 that time .

Will get back.
 
Instafixx

Instafixx

Active member
Q420 lines arent shorted.
PP2v5_AWAKE_NAND is 3.4V

Has an exact same issue before. Had replaced U7700 that time .

Macbook A2338 820-02020

Stuck at 5V drawing a constant 0.450Amps. PPBUS at 7-8V. I checked and found PP1v25_s2 to be 0.280 which I think is a little lower than usual. PP3v8_AON is 3.7V
boards.rossmanngroup.com boards.rossmanngroup.com
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
"Q420 lines arent shorted"
If no short, check its enable signal.
It shouldn't receive enable signal when the output voltage is present.
 
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