There is no sound but appears to be playing

@gjglum check your iPod by connecting it to a docking station of some sort and see if you can get the music from that. If you do you may just have a bad headphone jack. To repair that follow this guide. If you do not get any sound your iPod is having problems with the audio IC on the board. This particular model has a problem with an IC on the logic board. the solder on the audio IC does develop microcracks and loses contact with the logic board. You can try and see if you get sounds by applying some pressure to the right lower side of the ipod, almost between the click wheel and the bottom corner. If you should get sound by doing so, then you only have very few options. One is a new logic board for about $40 on eBay; the other one is to reflow your old logic board. Or you can try what warnergt did on http://forums.macnn.com/103/ipod-iphone-... By now I can verify that this works since I performed a reflow on three of the boards and it solved the problem.