820-3115 no green light no rail. It is not dc board.

[BCN_Techs]

Hi,

Got 820-3115 logic board with no previous damage, When plug magsafe there is no green light, there is no voltage on any rails. DC board is ok because connected to other board it works. Already tried with few board.

Tried to measure 5 pins on dc board and all them are at 0. It's like something is blocking magsafe.


Any suggestion?


Thanks

 

[2informaticos]

Leakage on input stage blocks the charger.
I bet you will get some voltages, maybe working board, using fake charger, or bench power supply.

Post exact value (onboard, ohm scale) for R7080/81 and R7085/86.
Usually bad Q7085.

Also check for any short on the board.
Be sure R7011/12 are both OK and no short at C7011.

 

[BCN_Techs]

R7080 97.8 Kohms
R7081 62 Kohms
R7086 317 kOhms
R7085 416 kOhms.


When i was checking i noticed that R6990/95 were burn When removed both i got 16V on Pin 1 R6990.

R7011/12 both are ok

Also changed Q7085 and the result is the same

 

[2informaticos]

R6990 can get burnt because of C/U6990.
R6995 never, as it has 1M; possibly corroded, yes.
Now D6995 possibly burnt too.
Check/change all them and be sure no short at L6995.

 

[BCN_Techs]

It was C6990 shorted to ground. Thank you very much 2informaticos.

Problem solved.

 

[BCN_Techs]

New issue detected.

Macbook runs from power adapter and battery. If run from power adapter and disconnect it it shuts down. If run from battery and conect than disconet the battery it shuts down.

 

[BCN_Techs]

D6990 was causing last issue. Thanks.