820-3115 fake Charging

Melvinzill

Member
Hi, I have this mid 2012 13” non retina here for repair. It initially wouldn’t power on no green light or anything but it works using a charged battery. If I plug in a charger there is no light, although it does show the little symbol on the top menu bar under System profiler it detects a Charger but says not charging. Anyone got a clue what to look out for on these?
 

2informaticos

Administrator
Staff member
What is the exact PPBUS_G3H, on charger only?
Does it work in charger only?
Some volatges of U7000?
Especially pins 9, 12, 13, 14, 15.

Also post exact voltage and diode mode at SCL/SDA lines of battery bus.
Did you try disconnecting BIL (J6955)?
 

Melvinzill

Member
Did some testing:

- Disconnecting J6955 makes no difference
- It doesn’t turn on with just a charger, however disconnecting the battery after it powered on causes it to continue working off the charger
- PPBUS_G3H with the charger only and the machine off is 12.62V
- Requested U7000 Voltages are:
Pin 9 - 0V
Pin 12 - 3.47V
Pin 13 - 3.448V
Pin 14 - 3.346V
Pin 15 - Test Pad like most others looked horrible, got 0V but if you see no other problem I’ll take the board out and measure from the resistor on the back
- The SCL Line of the Battery Bus is 3.47V and a diode Mode reading of .555
- The SDA Line of the Battery Bus is 3.48V and a diode Mode reading of .554
 
Last edited:

2informaticos

Administrator
Staff member
PPBUS_G3H voltage is correct, don't bother anymore with SCL/SDA lines.

You must get first the board booting on charger only.
Check continuity for ADAPTER_SENSE line from U6900 to central pin of Magsafe connector.
Did you try another DCIN board?
Battery cannot be charged, until you get Magsafe light.
 

Melvinzill

Member
Okay, I think problem solved! Turns out U6900 had corrosion on it. Replaced it and it appears to charge again and the light works again
 
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