820-00165 strange problem

[Patricia]

Hi to all

i have a 820-00165 that works perfectly fine from battery and charges from the bench power supply , green and orange present , ppbus 8.57 and pp3v42 is 3.42 but if i connect a known good (several) apple chargers i get no green light or flashing green every 3 seconds and it doesnt charge or turn on .
I replaced the dc in board and the flex cable and no change .
Absolutely no corrosion whatsoever , the region around the ISL and SMC are perfectly nice and no visible corrosion or even dust
Anyone have any idea ? I suspect that the communication between middle pin on charger and isl might be a problem but probably wrong .....

Thanks in advance

 

[2informaticos]

Very likely leakage on DCIN side.
If D7012 is good (not shorted), then change Q7180.

 

[Patricia]

Thank you dos informaticos , I see that after 10 months I was away nothing changed , its still you who works
I did check the D7012 for a short and it was ok , and replaced the Q7180 and it is unfortunately the exact same symptoms , a short green light
every 3 seconds and on the desk power supply it works just fine

Thanks for the reply

 

[2informaticos]

Check if R7012 has correct value (ohm scale).
Also describe PPDCIN_G3H behavior, with original charger.

 

[Patricia]

R7012 is 68k , PPDCIN_G3H is starting with 5,2v and going down slowly to 3.9v , with desk power supply its 18.4v as it should be ....

 

[2informaticos]

Original charger is smart enough to prevent full voltage delivery, if detects leakage on the board.

Post Q7010 voltages with lab PSU.
Also post R7180/81 and R7185/86 values; measured onboard, ohm scale.
Try changing Q7010.


"with desk power supply its 18.4v as it should be"
Is that the voltage marked on original Air (45W) charger???

BTW, there is no communication at all between SMC and charger.
1-wire memory (located into Magsafe connector) is nor even powered from charger, but from MLB.

 

[Patricia]

14.85 is the marked v on the charger but on the schematics its marked 18.5 v and that was what i refered to
The R7180 was hard to measure .... because it wasnt there Put in a 100k there and all works fine
Thank you dos informaticos for your help

 

[2informaticos]

Always respect voltage marked on the original charger.
You may trigger VD0R sensor sometime and SMC refuses to start in such case.