Acer E1-451 Notebook Does Not Recognize The Battery

 

Laptop model: Acer E1-451

 

Board number: 12276-1

 

Fault: The Notebook Does Not Recognize The Battery

 

Maintenance process:

 

After replacing the battery, there is still a red cross. The BAT_SDA BAT_SCL resistance is normal after disassembly and the battery is inserted. BAT_IN# is 2.1V when the battery is inserted. BAT_IN# is active at low level and should not be high when the battery is inserted.

The trace source is pulled up through R2775 and goes directly to EC. EC comes with a program, and without 809H, there is no way to refresh the EC program, so you can only be a dead horse. I remember seeing a post about another model before that just replaced the resistor of the battery interface.

 

I couldn't find the 330 resistor on the laptop's scrap board, but the Asus platform is more powerful. I removed it from the platform and replaced it, but the problem was still the same. BAT_IN# was also connected to a Zener diode PD3902, so I replaced it directly, but it didn't work. This problem has not been fixed before.

Suddenly I thought about whether it was a problem with the pull-up resistor. I measured that R2775 had 100K, which was normal. I found a 100K resistor and replaced it, but it still didn't work. But when I measured BAI_IN# again and plugged in the battery, it showed 3.3V instead of 2.1V. Try changing the resistor to a larger one.

 

　　Find a 200K resistor and replace it. Plug in the battery and measure BAT_IN#. It is low. You can turn it on by pressing the switch. Then you replace the customer's previous battery but it still can't be turned on. Then you replace it with a new battery and it still can't be turned on. 

    Measure BAT_IN# again. It's back to high level again. I have to listen to the captain's lecture in the evening and try changing a 200K resistor. It works fine with new batteries.

    This time I didn’t dare to use the old battery to turn on the phone. The old battery was probably broken. I tested the new battery for a day and found no problem. Charging and discharging were normal.

Happy Repairing !!