Macbook A2337 PPBUS Cycling

[Instafixx]

Board Number 820-02016
AMP Meter goes upto 20V and reboots. Same Behaviour on booth charging port.
Removed the FUSE getting PPVBAT_AON_CHGR_REG as 12.3V stable. Amp meter also stable npw.
No shorts on PPBUS, 3v8_AON, PP5v_s2.

 

[2informaticos]

Did you test with battery connected?
Any fault history available?

 

[Instafixx]

Yes with battery connected and disconnected. Same Pulsing behaviour.
Thermal Scanning shows UF015 heating up very lightly. Replaced it just in case. But still the same.

 

[Instafixx]

Please help me out here!

 

[2informaticos]

Check all secondary power rails for voltage pulse and diode mode.

Did you test the board alone on the desk?

 

[Instafixx]

PP3V8_AON_VDDMAIN stable at 3.8V
PP3v3_S2 is Pulsing from 0V to 3.3V
PP5V_S2 is pulsing from 0V to 5V
P5VS2_EN pulsing from 0 to 1.8V
P5VS2_FB_RC pulsing from 0V to 5V
P5VS2_PGOOD pulsing from 0V to 5V
PP1V8_AON_MPMU stable at 1.8V
PP1V25_S pulsing from 0V to 1.25V
PP1V2_S2 is pulsing from 0V to 1.2V
P1V8_AON_EN stable at 1.8V
PP3V3_AON is stable at 3.3V

this is board alone on bench

 

[2informaticos]

I meant power rails, not enable, or power good signals.

"P1V8_AON_EN stable at 1.8V"
UC120 output stable also?

All MPMU/SPMU LDOs are stable?
What about SSD power rails?

 

[Instafixx]

UC120 all voltages are stable.

PP5V_BSTLQ_VOUT_MPMU Stable at 5V
PP1V8_AON_MPMU stable at 1.8V
PP1V5_VLDOINT_MPMU stable at 1.5V
P3V3S2_PWR_EN_MPMU is pulsing.
MPMU_XTAL1_R stable at 0.25V
MPMU_XIN stable at 0.3V
MPMU_VREF stable at 1V
MPMU_VBAT stable at 0.1V
MPMU_IREF stable at 0V
PP1V5_VLDOINT_SPMU stable at 1.5V
PP1V8_AWAKE_SPMU_GPIO Pulsing
PP5V_BSTLQ_SPMU stable at 5V
SPMU_VREF stable at 1V
PP2V5_AWAKE_NAND is pulsing
PP0V88_AWAKE_NAND is pulsing
PP1V25_AWAKE_NAND is pulsing

 

[2informaticos]

You may have SSD problems...

 

[Instafixx]

SSD Replacement is the solution?

 

[2informaticos]

You can try that.
Think first if is worth to do it...