One of my friends had a 1st gen ipod nano that would not hold a charge, so he gave it to me to tinker with. I replaced the battery with a new one, but it seems to still have the same problem. It is read by my pc and im able to transfer files to it fine. As soon as I take it off the charger, however, it shows that it has a low battery and dies in around 10 mins. This happens regardless of how long I let it charge. What could be causing this? Is it fixable? thanks.