Macbook A2337 820-02016 (Stuck at 12.3V)

[Instafixx]

Is there any connection between U5200 and U8100.
i have replaced U5200 3 times.
After replacement PPBUS is 12.3V.

Then when i probe around U8100 to check and go back to check PPBUS it drops to 1V.

 

[Instafixx]

???

 

[2informaticos]

U8100 requires 3V8_AON, not PPBUS_AON directly.

 

[Instafixx]

I have replaced U8100 but again PPBUS dropped to 1V.
Replacing U5200 again. Now for the 4th Time.

Something is shorting U5200 again and again. Please guide me what it is.

 

[Instafixx]

Replaced U5200
Replaced U8100.

PPBUS at 12.3V
3v8_aon at 3.8V

But still the same as before.
3V3_S2 is still 1V.

 

[Instafixx]

U8100 LDOs
MPMU_VREF_ADC is 0V
PP3V3_S2_UPC is 1V
PP1V2_S2 is 0.5V
PP3v8_AON_VDDMain 3.8V
PP1V5_VLDOINT_MPMU 1.5V
PP1V8_AON_MPMU is 1.8V

NO SHORTS.

U7700 LDOS
While checking i found
PP5V_BSTLQ_SPMU shorted to ground. OpenboardData shows diode reading to be 0V but i doubt it. Can you confirm ?

 

[Instafixx]

Solved the Short on PP5V_BSTLQ_SPMU.
But i am getting 1.5V on that line.

Now 3v3_s2 pulsing from 1V to 2.5V but still not stable.

Replaced U7700. Still its the same .

 

[2informaticos]

That is 5V boosted out by U7700; can't be shorted to ground.
Try voltage injection method.
You may need to replace L7800 too.

 

[Instafixx]

Tried Voltage injection method and removed the short.
Then found 1.5V on that line.
Then replaced U7700.
Still the same 1.5V.

Let me replace L7800 and get back.

 

[Instafixx]

Replacing L7800 Solved it. Thanks