I bought a X220 Tablet this past summer. A couple of days ago I was using the laptop plugged in when it popped up saying that I was on reserve battery. Thinking the plug had just come unseated, I unplugged and replugged the power supply from the back. The computer though refuses to think it is plugged into the power supply. It still gets power from a battery. I tested to make sure that it wasn't just a power supply issue by borrowing a known working one from a friend, which the computer also refused to recognize.
I was just wondering if this is a known issue of the plug going bad in the X220s, and if there was some fix before I took it into the repair center.
Dug through the forums for a bit after posting and found a similar problem in an X41. Played around with the instructions, and to my surprise my computer is now functioning again. Posting this here for anyone else that has a similar problem.