Not charging or syncing via USB, charges via Firewire
Recently acquired this as 'non-working.' Battery was completely drained. Plugging in to USB, it briefly shows as charging, then reverts to not charging, but apparently able to run off the power provided by USB. It also doesn't show up as a disk or in iTunes.
A firewire connection will provide the 'not supported' screen, but allow it to charge.
There have been some similar problems reported here that suggest a bad battery may cause behavior like this, but none seem to indicate that this is actually the solution. So is it a battery issue, or is the USB on this toast?