820-3462 A1425 NO POWER

[Jeffotskie26]

customer say lastime can power on fan was spinning so fast until the macbook dies.
no sign of corrosion sometimes have green light most of the time dont have light on magsafe

PPBUS_G3H 12.26v
R7020 16V

U7000
1 0v
2 16.3v
3 3.9v
6 3.4v
9 0v
12 3.4v
13 3.3v
14 3.1v
15 0.1v
17 12.28v
19 5.5v
20 5.5v
27 16v

 

[Jeffotskie26]

SMC_RESET_L 3.3v
tried change q7080 u7000 and dc in board no changes

smc chip issue?

 

[2informaticos]

Post voltage and diode mode to ground at SCL/SDA lines of battery bus.

 

[Jeffotskie26]

SMBUS_SMC_5_G3_SCL 0.527 3.4v
SMBUS_SMC_5_G3_SDA 0.522 3.4v

 

[2informaticos]

Do you get 12MHz oscillation at Y5010?
Check what happens reballing SMC.

 

[Jeffotskie26]

smc reballed nothing happens ppbus still 12.26V
i have osci but i dont know yet how to use it,
can give a little knoledge how to use it?

 

[2informaticos]

If can't confirm oscillation, check for DC voltage at Y5010 pins; should get around 1-1.2V DC.
If 12MHz oscillation is there, SMC should work; change it, if not.