AcerE1-451 notebook does not recognize battery repair

Machine model: Acer E1-451

Plate number: 12276-1

Fault phenomenon: the notebook does not recognize the battery.

Maintenance process: the battery is still a red cross after replacement, and the resistance of BAT_SDA BAT_SCL is normal when disassembled, and BAT_IN# is 2.1V when plugged in, and BAT_IN# is effective at low level, so it should not be high when plugged in.

AcerE1-451 notebook does not recognize battery maintenance Figure 1

Tracing the source was pulled up through R2775 and went directly to EC. EC comes with a program, and without 809H, you can’t brush the EC program, so you can only be a dead horse as a living horse doctor. I remember reading a post on other models before that it would be good to replace the battery interface.

No 330 resistance was found on the waste notebook board, but it was still powered by ASUS bedplate. It was still the same if one was removed from the bedplate and replaced with a fault. BAT_in# was still connected with a zener diode PD3902, which was directly replaced, but it was useless. I haven’t fixed this problem before.

AcerE1-451 notebook does not recognize battery maintenance Figure 2

Suddenly, it occurred to me whether it was the pull-up resistance. It was normal to measure R2775 at 100k, but it was still not possible to find a 100K resistor to replace it. However, it was 3.3V, not 2.1V, for the BAI_IN# plug-in battery. Try changing the resistance a little higher.

Find a 200K resistor, plug in the battery and measure that BAT_IN# is low, and press the switch to turn it on. Then, the customer’s old battery can’t be turned on, and the new battery can’t be turned on, and BAT_IN# returns to high level. I have to listen to the captain’s lecture at night, and try changing a 200K resistor. It’s no problem to use a new battery.

AcerE1-451 notebook does not recognize battery maintenance Figure 3

I didn’t dare to use the old battery to start this time. The old battery should be broken. The new battery has been tested for a day, and the charging and discharging are normal.