820-2850 intermittent charging

board will take a few try for MagSafe to turn on green light and then turn to orange light but will turn off the light without completely charging the battery. Have to remove charger and try again a few times for it to resume charging.

the same charger and battery on a different 820-2850 board have no such issue. where to start?

Did you try another DCIN board?

ok, replaced DCIN board seems to fix the problem..

sorry the problem come back... swapping good battery and it is now doing intermittent charging.. it will charge and then turn green for a while and then it will go to orange and then green...


When the light is green, PPVBAT_G3H_CHGR_R is 12.99v
when the light is orange, PPVBAT_G3H_CHGR_R is 11.62v

batt sdl/sda = 3.3v, charger is original 85w charger.

u7000 voltages when it is green.

1 = 0v
2 = 15.8v
3 = 3.88v
9 = 0.62v
12 = 3.4v
13 = 3.4v
14 = 3.26v
15 = 0.072v
19 = 5.1v
20 = 5.02v
27 = 16.4v

Inspect U6900/1 areas for corrosion.
Clean DCIN board and Magsafe connector as good as possible.

U6900/1 areas is very clean with no corrosion.

Cleaned DCIN and Magsafe connector already, tried 3 genuine adapter and still the same.

PPVBAT_G3H_CHGR_R is 12.99v normal?!

I also found out that sometimes it will stay orange and in such case PPVBAT_G3H_CHGR_R = 12.07v

If i remove the battery, the voltage at F7040 is 12.6v

12.6V is correct voltage without battery connected.

PPVBAT_G3H_CHGR_R must have all the time same voltage as PPBUS_G3H; no matter battery is connected, or not.

Just in case, try bypassing R6950.
You can also remove D6950.