Is it the logic board?
computer or itunes does not recognize ipod.
If other USB devices (Flash Drive etc.) work in the same USB port then you can rule out your computer as the problem. It is most likely a faulty cable. If you have another cable or a friends cable, you could try that and see if you can rule out the cable. otherwise it will be the ipod.
Take a look at the plug on the ipod that the cable plugs into I had the same prob on a 5th gin vid I fixed the plug on the ipod and that fixed it