MacBook A1990 - 820-01814 Board - Works but no battery detect

[GoodguyFR]

Hi people,

Here I have a strange case from this A1990. It came from an other shop, and was initially took in charge for battery replacement because it was inflated.

When I took it in charge, The Mac run fine on battery and also on charger when battery unplugged, but It has a charging issue. Three differents battery has been tried, and also battery cable. I can see charging spikes when the Mac is off and battery plugged. It goes to 0,8A for 2-3 secs, and goes to 0A, cycling. The battery pourcentage was shown in MacOS.

Then I found light oxydation on one of the CD3215, I replaced it and some caps and R around. No change. With a thermal cam I saw Q7030 getting hot when charging spikes come, I replaced it. From this point, the battery pourcentage was not shown anymore on MacOS. The Mac can still run on battery and charger.

Then I replaced R6910 because of bad reading (15k instead of 4.7k), no change.

I checked current sensors around U7000, they were fine, I replaced Q7040 and Q7065, and also U7000.

This is the last thing I have done on this board, the behavior is still the same, I have a pretty bad understanding of what is going on and why the battery works, but cannot charge and being shown on MacOS.

I really appreciate to have a little help on this one, thank you.

 

[2informaticos]

The heat applied when you've changed Q7030 affected something more on the board.
Or you may have knocked off, or moved components there.

I can't find R6910 in schematic.
Be sure R6950 is good.

Check voltage and diode mode to ground on SCL/SDA lines; before and beyond Q6950.

BTW, if a component gets hot, doesn't mean is (always) bad; there can be some other reason for such behavior.

 

[GoodguyFR]

Hi 2informaticos,

Thank you for your reply ! R6950 was missing, probably knocked off as you mention it, and indeed R6910 does not exist on schematics, but it does on the boardview, very strange. On the boardview it is the resistor next to Q6950, connected to his pin4. I can't find anything to match with on the schematics, and I am starting to ask my self, how the fuck did I changed this resistance if it is not shown on schematics...

At first I replaced it with a 4.7k first, don't know why I chose this value, it was in fact a 0omh. I replaced it and now it works fine.

Thank you for your expertise, first time I solved an issue through your forum

 

[2informaticos]

Glad to hear I helped.

R6910/11 are just 0 ohm resistors; series protections for T2's SMBUS.
Not figured in schematic, but easy to "guess" the value interpreting the boardview.