My 80gb Classic Ipod Doesn’t Charge In The Speaker Dock Anymore. How Can I Fix This?

It used to charge all the time whenever it was in the speaker dock, but as of late won’t charge anymore. I update the ipod whenever new updates are found on itunes. There is a way to restore the ipod to what it was before all the updates were installed, but I’m not sure if that is the way to go about it. Please help!