[SOLVED]820-3476 does not charge battery

[Cocobill]

Hello again,

an 820-3476 that does not charge the battery. There was corrosion on pins 22 23 24 of U7100. Also, a burnt trace from pin 23 to C7125. I removed the ISL, cleaned up the area, put a new ISL in, put a wire from pin 23 to C7125. It still sees but does not charge the battery. Resistance 17/18 is 4.3Ohm and 27/28 20.8Ohm.

Any ideas?

 

[Cocobill]

Battery looks good. I got it at 65% capacity. Load cycles are at 921. As I am doing the tests with the charger plugged in, it slowly discharges and is at 33% now. It boots off the battery just fine. I have no other known good battery to test, though...

 

[JohnB8812]

Try another battery and MagSafe board just to be safe. What is your voltage on PPBUS?

 

[Cocobill]

unfortunately I have no other battery to test. I changed the MagSafe board and

PPBUS_G3H measured on R7005:

charger and battery: fluctuates between 12.50 and 14.50 or so within a second
charger only: 15.39V
battery only: 10.92V

 

[JohnB8812]

15.39 is way too high for PPBUS. Sounds like a shorted Q7130. Replace the ISL, Q7130 and Q7155 all at the same time and see what happens.

 

[Cocobill]

So I took another MacBook apart and put this logic board in. Same thing, it does not charge a known good battery. Will change these three chips you are proposing and get back to you tomorrow.

 

[Cocobill]

I changed ISL with new one, took Q7130 and Q7155 from Aliexpress doner board, and now I get an on/off green light flashing every other second. Fan is spinning. I took another pair of Q7130 and Q7155 from a known good board, same green light flashing.

 

[Cocobill]

And after changing the ISL another time, it worked! Battery is charging beautifully! You can close this case. Thank you all for your help.