3115 B, some times green light some times not, not turning ON!

[Noguinfor]

hey,

working on board 820 3115, no signal water damage!!

ppbus = 12.56v

PP3V42_G3H = 3.42v

PPVRTC_G3H = 3.3V

PP5V_S5 = 5V

PP5V_SUS = 5v Green light ON, 0V green light OFF

PP5V_S3 = 0V

PP5V_S0 = 0.228V

PP5V_S0_HDD = 0.228V

Already replace 51125 and Same history!

suggestions??

 

[2informaticos]

"PP5V_SUS = 5v Green light ON, 0V green light OFF"
Seems that PM_SLP_SUS_L is not stable.
Check for basic signals:
SMC_RESET_L, SMC_BC_ACOK, SMC_PM_G2_EN, SMC_ADAPTER_EN.
Post voltages for U6900/01.
Check continuity from U6900 to central pin of magsafe card.

 

[Noguinfor]

SMC_RESET_L - 3.4V

SMC_BC_ACOK - Unstable 3.3V - 3.1V

SMC_PM_G2_EN - 3.4V

SMC_ADAPTER_EN - 3.4V

U6900 - Pin1: 3.4v, pin4 and Pin5: unstable 2.8v - 2.9v

continuity it's ok !!

 

[2informaticos]

Stable 3V3_S5?
S5_PWRGD present?
Try to reflow SMC...

 

[Noguinfor]

All voltages are present! SMC refowed and machine comes to the life!! which is more indicated reballing SMC or replace to another one??

 

[2informaticos]

If no liquid sign, reflow should be good enough.
Reballing is better, in theory; if you don't fail in the process...

 

[Noguinfor]

Ty 2informaticos!!! ​​​​​​​