Macbook A2337 820-02016 (Stuck at 12.3V)

[Instafixx]

PPBUS is 12.3V Stable
3.8V Present
3v3_s2 absent - no shorts.

3V3S2_EN is missing as well.

PP3v3_S2_UPC also missing.
Bad U8100 ?

 

[2informaticos]

Any fault history?
Do you get other MPMU LDOs?

 

[Instafixx]

3v8 Present
1v5_VLDOINT_MPMU Present
5V_BSTLQ_MPMU Present

 

[Instafixx]

Hello, Please help.

 

[2informaticos]

Diode mode 3V3_S2_UPC?

 

[Instafixx]

Now Suddenly PPBUS is 2V
Removed Fuse. Still same 2V
Replaced both CD3217 and U5200. Still the same.

 

[2informaticos]

C5254 voltage, with F5200 removed?
If low, post U5200 basic volatges (with fuse removed).

 

[Instafixx]

It is low. But i have replaced U5200 already.
Still need the voltages ?

 

[Instafixx]

P_IN is 5V
AUX_DET is 1.2V
SMC_RST_IN is 0.1V
VDDA/P both 5V
EN_MVR 0V
AUX_OK is 0.1V
A/BMON both 0V

No Shorts on any of the rails

 

[2informaticos]

AUX_DET is good, but AUX_OK isn't.
Reflow U5200; if still the same, replace it.

 

[Instafixx]

Replacing U5200 solved PPBUS back to 12.3V.
But original issue remains.
S2 rails missing
3v3_s2
1v25_s2

 

[Instafixx]

Please reply

 

[2informaticos]

Check all U8100 & U7700 LDOs.
If any missing, check in diode mode too.

 

[Instafixx]

Again PPBUS has gone down 1V.
There is some issue which i think i am not able to figure out.

Please guide?

 

[2informaticos]

Check again C5254 voltage, with F5200 removed.

 

[Instafixx]

Its 1V with fuse removed.
Something is damaging U5200 again and again i feel.

 

[2informaticos]

Bad solders maybe.
Did you try to reflow it?

 

[Instafixx]

U5200 issue resolved with reflow.


U7700
PPVDD_PMU_LDO_PREREG is 0.1V

Can you help with the LDOs of U7700 and U8100 so that i can check them?

 

[Instafixx]

U5200 issue resolved with reflow.


U7700
PPVDD_PMU_LDO_PREREG is 0.1V

Can you help with the LDOs of U7700 and U8100 so that i can check them?

 

[2informaticos]

You should check U8100 first; is the master.

For the missing LDOs, check in diode mode and compare with good board.