820-3787 Burning Batteries

brunomotter

Member
Hello! Got an 820-3787 here with a strange symptom! It was not turning on. I found a shorted cap near J5250 area, cleaned the area and replaced the cap and the board tuned on. No corrosion at all nowhere over the board but the J5250 area. I replaced the battery with a new one because the original was swollen. Gave back the machine to the costumer. 10 days after he returned and the battery was not recognized anymore. Sent the battery to RMA and got a replacement. The replacement did not even work. Sent it back again to RMA and today I received the new one. I put it on the machine again and the machine started with the new battery. Thought the problem was solved. Glued the battery into the machine and assembled the computer again. When I tried to turn it on the machine did not recognize the battery again and the OS says to replace the battery immediately. If I remove the magsafe charger the machine dies immediately and does not charge the battery. Any ideas on where to start? It's very unlikely that I got 3 bad batteries with the same defect!
 

brunomotter

Member
I do not have one. This Macs rarely show up here and I do not have any battery of this model here. Anyway, this battery is supposed to be original, the system even recognizes it as being made by SIMPLO.
 

2informaticos

Administrator
Staff member
I still recommend to test known good one.
You can risk to waste time for nothing.

Just in case, check SCL/SDA lines in diode mode.
Be sure R7050 is OK.
Run ASD too.
 

brunomotter

Member
I would definitely test another KG battery if I had one, but I don't have it! Will verify those lines and post back here
 

2informaticos

Administrator
Staff member
Few days ago I received A1286 (3330) which gets stuck when battery is fully charged 100%; new (chinese) battery.
It doesn't start from battery alone, nor charger + battery, when battery is 100%; need to remove the battery...
The machine works perfectly, no other issue.
I just tested an old (inflated) battery, and all good.
I posted to explained what weird problems can generate a crappy battery...
 

brunomotter

Member
I understand that, but as I told, I do not have access to another battery and this is the third one my supplier has sent me?
 

brunomotter

Member
R7050 is reading fine. 10k precisely.

Diode mode readings(red probe on GND, black on line)

SMBUS_BATT_SCL = 0.480
SMBUS_BATT_SDA = 0.490

I measured those lines on pin 5 and 6 of J7050 respectively.
 
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brunomotter

Member
No I don't... I got a new battery today(supplier sent a new one) but I'm afraid of putting it in and burn it again, like it happened to the other 3 batteries...
 

2informaticos

Administrator
Staff member
Try old battery.
If reports some charge, then turn off the machine, disconnect charger and check 3V42.
If no good, then verify R/D7005...
 

brunomotter

Member
It reports 79%, not charging and the battery status on system is Replace Now. If I unplug charger the machine dies immediately. 3.3V is present with charger, when I disconnect charger the machine dies and PP3V42_G3H goes to 0V. I plugged in the last battery this computer burned.
 

brunomotter

Member
No offense but this sounds 100% like a fucked battery
That's exactly the problem... I tried 3 batteries... All of them work for some minutes then die... It's very unlikely that I got 3 fucked batteries... I think this machine has some kind of intermittent short that's killing the batteries... Besides, I do not buy cheap batteries... I always buy the best batteries I can to avoid problems, and this supplier alway sells me good batteries, just this machine is giving me headache!
 
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