820-3332-a not turning on

[BCN_Techs]

Hi,

Got 820-3332-a that cutomer changed U8900. No liquid damage, as he says just display randomly was shutting down. Changed U8900 again with new one ( it wasnt soldered good). The machine still not turning on. Green light ok. PPBUS_G3H 2.2V and almost shorted to ground with 11ohms ground resistance.


With magsafe contected U8000 is getting warm enough. Already checked ISL 625 and 17/18 and 27/28 resistance seems to be ok. Also resistance in that area.

I guess that when was changind U8900 first time heated up too much and fucked GPU. CHecking in that area doesnt see anything strange.

Any idea?

 

[2informaticos]

Post diode mode to ground on F7040 and L8930/60; there is GPU VCORE.
You can also remove Q8930 and check if PPBUS_G3H has then correct value.

 

[BCN_Techs]

Customer doesnt want to wait. So thanks for help, Macbook was given to it's owner.

 

[JohnB8812]

For the best they fucked it not worth the time