820-00138 A1398 2015 - Not turning on when battery is connected

Saurabh

Member
- With the battery disconnected, the device turns on with direct power and works perfectly fine.
- Connected the battery while the machine is on. Battery being detected and charging fine.
- Device won't turn on with the battery connected. Same behaviour with known good battery and minimal components connected to MLB.
- Inspected MLB under the microscope. Clean.

Not sure where to start. Please help me.
 

2informaticos

Administrator
Staff member
Post F7140 voltage w/ and w/o battery connected.
Check exact resistance between pins 17/18 and 27/28 of U7100.
 

Saurabh

Member
F7140:
With battery, charger connected - 12.32V
With battery, no charger - 11.67V
Without battery, charger connected - 12.61V
Without battery, no charger - Hovering around 1.5-1.4V.

U7100:
Resistance B/W 17/18 Without charger - 2.8 ohms
Resistance B/W 17/18 with charger - 2.649 Mega ohms

Resistance B/W 27/28 Without charger - 21.8 ohms
Resistance B/W 27/28 with charger - 21.2 ohms
 

2informaticos

Administrator
Staff member
WHAT???
Did you check resistance on powered board????????????

"Without battery, no charger - Hovering around 1.5-1.4V."
This also "amazing"; what voltage did you expect on the board without any power???
PLEASE, put some logic on your job!

Check again resistance between pins 17/18; remove charger and battery first!!!

Does the board turns on with battery alone (no charger)?
 

Saurabh

Member
Sorry for that.

Resistance BETWEEN pin 17/18 - 3.9 ohms
Resistance BETWEEN pin 27/28 - 21.8 ohms

Yes, board turns on with battery connected, freezes on apple logo. Also reprogrammed BIOS with cleanME, same behaviour.
 

2informaticos

Administrator
Staff member
With both battery and charger connected, board doesn't turn on pressing power button?
Check if SMC_ONOFF_L drops when pressing the button.
If not, use R5115/16 pads, instead of battery bus.

Any history available, liquid signs?
 
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