Error 0190: Critical battery error

[QWERTY Andreas]

Hi
I got a T500 cheap, that didn't Work with an AC adapter, and i have been trying to fix it.

The machine Works fine, on battery power.

When it is started up on AC, it will bring the "Error 0190" error, and i have tested with working adapters and CMOS batteries. So it should be fine.
However it is just stuck there. If i start it on batterypower, let it boot, and remove the battery - the computer Works just fine!

Does anybody have a solution to this problem? Or is the motherboard dead?

Best regards