MacBook A1425 2012 820-3462 No Green Light.

arshees

Member
Hi,

Need help with 820-3462 board. Initial state machine used to turn on after connecting power for a few hours and battery status missing. Could not enable battery status. Reconnecting the battery solved the problem but same issue next day. This went for a few days and now no green light and no power on. No liquid damage and untouched board. Initial voltage check as under..


PPBUS_G3H 12.30V
PP3V3_S5 – 0.04V
PP5V_S5 - 0.01 V

PP5V_S4 - MISSING

PP3V42_G3H – 3.44 V

PP5V_S0 – MISSING


SMC_RESET_L 3.0V
PM_PWRBTN_L - MISSING
PM_RSMRST_L 3.3V
SMC_ONOFF_L 3.3V

What do i check for next..
 

arshees

Member
Further voltage checks...
G3Hot" Rails

PPBUS_G3H – 12.28V
PP3V42_G3H – 3.44V
PPDCIN_G3H – 16.52V

5V Rails
PP5V_S5 – 0.40 mv
PP5V_SUS – 25.4 mv
PP5V_S3 – 0.06mv
PP5V_S0 – 0.74mv

3.3V Rails
PP3V3_S5 – 0.23 mv
PP3V3_SUS – 0.03mv
PP3V3_S4 – 0.10mv
PP3V3_S3 – 0.01mv
PP3V3_S0 – 0.01 mv


3.3v and 5v rails missing. What do I look for… I am new to macbook repairs and appreciate some help..
 

2informaticos

Administrator
Staff member
Seems that SMC doesn't run.
Check signals and voltages for U4900 (2 OF 2), page 39.

SMC_PM_G2_EN comes high?
 

arshees

Member
SMC_PM_G2_EN - 006mv.. Since i don't have a scope, i cannot give you the required signal readings.. voltage reading as follows..
G10 - SMC_RESET_L - 3.21V
D7- VDD - 3.42V
I know this is not much of a help... anything else i can check...
 

2informaticos

Administrator
Staff member
If no o-scope available, post at least DC voltage for Y5010.

I was expecting VDDA/C voltage for U4900 too.
 
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