Solved! Laptop keyboard stops working whenever AC is unplugged

[bridge.adam]

The integrated keyboard on my Dell Latitude E6440 stops working as soon as the AC adapter is unplugged. If the AC is reconnected is still doesn't work, though a USB keyboard is fine. After flashing the bios with the bios update from the dell website, it works again. I'm totally confused. Does anyone have any suggestions?

 

[helpstar]

if it works now, the BIOS update fixed it

 

[bridge.adam]

if it works now, the BIOS update fixed it

But the problem is if I unplug the AC the keyboard stops working again, until I re-run the update.

 

[helpstar]

That´s different. Sounds like an empty BIOS/CMOS battery. Try replacing it:
https://www.youtube.com/watch?v=JcCNzR-ffjM

 

[bridge.adam]

That´s different. Sounds like an empty BIOS/CMOS battery. Try replacing it:
https://www.youtube.com/watch?v=JcCNzR-ffjM

Yep, I've tried that too. The cmos battery reads 3V on my multimeter and the system clock stays set when the AC and Li battery are both disconnected.

 

[helpstar]

Maybe the Li battery is faulty.

But it should be hardware related, if it doesn´t work with Ubuntu live too, booted from an usb flash drive

 

[bridge.adam]

Maybe the Li battery is faulty.

But it should be hardware related, if it doesn´t work with Ubuntu live too, booted from an usb flash drive

Yes, I was thinking to try a live distro, although I expect it will be the same in Linux as the bios menu is affected. I did buy a new battery not long ago although it seems to work fine otherwise.

 

[helpstar]

Are you sure the new battery provides the correct voltage and current for your laptop?