Macbook A2337 (820-02016) PPBUS 1V

[Instafixx]

Machine not turning on.
AMP Meter stuck at 5V.

PPBUS_AON is 1V.
Diode Mode Reading to Ground is .511

No sign of corossion on the board.

Getting 5V on C5201.
R5261/62 is 1.3 Ohms
R5221 is 1.3 Ohms
R5222 is 31.2 kOhms.

Should we replace R5222 ?

 

[Instafixx]

Replaced R5222.

Now the value is fine.

PPBUS_AON is 12.2 - 12.3V. Going back and forth.

 

[Instafixx]

PP5V_S2 is 0V and Diode Mode is 0.280

PP3v3_S2_UPC is 0.2V and 0.452

PP1v25_S2 is 0.03 and 0.290.

P5VS2_EN is Missing.
PPBUS_5VS2_VIN = PPBUS_AON.


Should we go for a DFU Revive.

 

[2informaticos]

Be sure first no short on any secondary power supply.
Do you get expected LDOs from U7700 and U8100?

 

[Instafixx]

I have mentioned the LDO Readings

PP3v3_S2_UPC is 0.2V and 0.452

PP1v25_S2 is 0.03 and 0.290.

 

[2informaticos]

Really, are these all???

Is it recognized in DFU at least?

 

[Instafixx]

Can you please help me with the other LDOs.

Not recognised in DFU.

 

[2informaticos]

I just realized you didn't say anything about 3V8_AON...

 

[Instafixx]

3V8_AON_VDDMAIN is 3.8V

 

[2informaticos]

Then check the expected LDOs from pages 34 & 29.

 

[Instafixx]

Page 29. LDO of U7700

pp1v23_s2
ppvdd_pmu_ldo_prereg
pp1v06_s2sw_dram
pp0v8_s1

all are 0V. Should we check further ?

 

[2informaticos]

That is the slave PMU.
You should start with master U8100.
In fact, I mentioned first page 34...

 

[Instafixx]

U8100

PP1v5_VLDOINT_MPMU
PP1V2_S2 is 0V
PP3v3_s2_upc is 0.1V

 

[2informaticos]

MPMU_VREF_ADC missing also?
If none of these LDOs is shorted (or very low resistance) to ground, then bad U8100.

 

[Instafixx]

Yes MPMU_VREF_ADC is missing too.

All have good diode mode readings.

Should we remove and re install or replace ?

 

[2informaticos]

Ideally replace with known good.
If you have doubts about solders, reball and resolder it.

 

[Instafixx]

Just posting LDO Diode Mode Readings again before ordering the PMIC.

3v8_AON_VDDMAIn is .172
PP1V5_VLDOINT_MPMU is .238
PP1V2_S2 is .353
PP3V3_S2_UPC is .465
MPMU_VREF_ADC is .586
PP1V8_AON_MPMU is .457


Are these okay. Should i order a PMIC

 

[2informaticos]

Use reference table, if no good board available for comparison.

OpenBoardData Project

 

[Instafixx]

Replaced U8100 with a new chip. Still the same.

 

[2informaticos]

Do you get its LDOs now?