820-4924 Green led 5 sec and shut down

[raainxx]

Hi,
i have this board, i have a green led with an original 85W magsafe2, the green led shutdown after 5 sec and come back after some seconds.
With a PSU, the led stay green and become orange. No liquid damage, the customer put a bad power supply on this mac.
i can't verify voltage with the original pw adapter.
i find a bad R7105 40K instead of 20ohm, i change it but same problem.
The mac work on battery charged.
I don't know where i check, can you help me please?
thanks

 

[2informaticos]

Usually leakage on Q7180, or Q7010.
Post Q7010 voltages with original charger.
Also post exact ohm value for R7012, measured onboard.
Check D7010 if short, or open.

 

[raainxx]

R7012= 5,6Kohm
pin 5-6= 17V but not stay.
pin 1-2-3=17 but not stay
i change Q7180 & Q7010? R7012 too?
D7010 seems good (0,78V & 0L other way).

 

[2informaticos]

"R7012= 5,6Kohm"
Leakage for sure.
Start changing Q7180
Be sure R7012 is not corroded...

 

[raainxx]

ok i try tomorrow to change it and i tell you after.
i don't understand and you can explain me, why the original charger stop to send the power? the mac talk with the charger?

 

[2informaticos]

Because original charger is "smart" enough.
It has an embedded processor, which first needs to properly detect the expected board!

 

[raainxx]

hi 2informaticos, I change Q7180 and R7012 became at 68K.
The green led stay with original charger, repair done, thanks a lot.