820-2838-a problem with powering up. fan spin for 1 second and stop

[speedyaction]

I have 820-2838-a board with problem. when i press power button fan spin for second and stop after nothing happen. any idea? aha. i bought this laptop with faulty magsafe. when i got it there was no green light on charger. i replaced macsafe board and now i have green light

 

[jadao]

The faulty magsafe maybe killed the charging circuit or the charger sense circuit.
What voltage do you get on ppbus_g3h?
Resistance between pins 17-18 and between pins 27-28 of U7000?

 

[speedyaction]

i checked straight away that first and is ok : ppbus_g3h -8.43v resistance also good pin 27-28: 20.5ohm and 17-18: 3.1ohm

 

[dukefawks]

CPU Vcore coming on?

 

[speedyaction]

no vcore voltage

 

[dukefawks]

Power good issue then I bet. ALL_SYS_PWRGD coming high, if not find the rail that is missing.

 

[speedyaction]

ALL_SYS_PWRGD no voltage at all

 

[speedyaction]

is this voltage should be show when computer is of? PP3V3_S3_FET also i have missing PP5V_S3_REG

 

[dukefawks]

PP5V_S3 must come high if the fan spins.....