Question My laptop won't boot up on battery, but can work with battery after removing the adaptor

[fybd88]

Thinkpad X1 Carbon Gen3 (2015). One week ago I tried myself to change the thermal paste, but harmed the fan insertion plug site. I also had a hard time removing the battery plug from the motherboard. After that, it seemed the battery plug can not be plugged as deep as before.

I went to a repair store to replace the damaged fan insertion plug. Then the laptop cannot boot on battery, however after booted with the connected adaptor, it can continue to work with the battery if I unplug the adaptor. The battery is also able to be charged with the adaptor, and the battery volume seems file in win 10. I went to the repair store again, the engineer told me there as nothing wrong with the battery plug. Lenovo's certificated repair store can only replace the whole motherboard, which is quite expensive for a 8-year-old laptop. What can I do to try to fix? Thank you!

 

[helpstar]

replace the connector inside the laptop between battery and motherboard, eventually the plug between battery and motherboard connector. Try a different battery

get a power bank with appropriate connector to the laptop for mobile use, if you wanna boot without charger

 

[fybd88]

replace the connector inside the laptop between battery and motherboard, eventually the plug between battery and motherboard connector. Try a different battery

get a power bank with appropriate connector to the laptop for mobile use, if you wanna boot without charger

That's rational analysis. The laptop is already aged, and the plastic on the motherboard has been fragile, so that I might try not to repair the motherboard as far as I can. I can go with a charger if the problem is not easily fixed.
I installed Lenovo diagnostics and found nothing wrong with the battery, and I updated the BIOS, but the problem continued.
Other similar posts suggested the CMOS battery went out, could that be the problem? The date inside the BIOS keeps up to date. Others suggested to push the reset button, which I didn't find.

 

[helpstar]

cmos battery could be the culprit as well, even if the date and time is correct

 

[fybd88]

The date and time was correct. I changed the CMOS battery, but the problem is still there.

cmos battery could be the culprit as well, even if the date and time is correct