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820-3115 wont power on on battery

I

ielectron

Member
not water damaged

customer says he replaced the battery and saw some sparking

it turns on on charger, there is green light, but very slow
-when battery connected wont change to orange light
-only on the battery wont power on
-when powered on with battery and charger, then i remove the charger it stays on, its just wont power on only on the battery

rarely wont even power on with charger, in this case the g3h is only 4.4V instead of 12V

i replaced u7000 and q7055, same
reflowed smc , same


the 10 ohm resistors are good, 20ohm measured on the cap, and the 2.2 and 0 ohm is good as well, 2.9ohm measured on the cap
 
2informaticos

2informaticos

Administrator
Staff member
Did you check resistance between pins 27/28, as 17/18 too?
The battery is recognized at least by macOS?
 
I

ielectron

Member
i replaced u7000 again, cause g3h was 4.4v, it died, so now it powers on again

resistance measured on the u7000 legs 27/28 22ohm, 17/18 3.8ohm, so the tracks are good from the resistors


osx doesnt see the battery at all, and if i remove the charger the screen goes black and never comes back but it stats powered on,

-fan is running high all the time, i guess it doesnt detect the battery temp?


on q7055
without charger:
pin 5 : 11.5V
pin 4 : 4.4V

with charger:

pin 5 : 11.5V
pin 4 : 12V


r 7050: 12.24V both sides

it has i5 cpu, all 4 cores are going 100% in the activity monitor
 
I

ielectron

Member
smc reset, and pram reset works

i had to reball the smc a few time on these a1278 macbook, could it be the smc, the customer mentioned saw spark when he replaced the battery
 
2informaticos

2informaticos

Administrator
Staff member
SMC doesn't communicate with U7000 and battery; that's the reason of 12.24V at PPBUS_G3H.
Valuable information, which you didn't post in the first post.

Check voltage and diode mode on SCL/SDA lines of battery bus.
 
I

ielectron

Member
battery connector pin 6 is 0.14v in diode mode, black probe on gnd, 0.4V only

pin 4 is 1.14V, and that has 3.3v

removed the protection diode d6950, same, something pulling down the line
 
2informaticos

2informaticos

Administrator
Staff member
Diode mode MUST ALWAYS be measured with red probe on ground...

Did you disconnect BIL?
Then only remain U7000 and SMC.
Also check R5280/81.
 
I

ielectron

Member
so it turned out the new battery somehow killed the that part of the smc and the battery indicator light, and eventually the u7000

so i replaced the u7000 then the smc, and just not connect the BIL (who needs that), and it works fine now
 
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