A few weeks ago I accidentally swept my Rio Carbon MP3 player from the table. Unfortunately it fell on it's weakest spot: the click wheel. Today I took the time to attempt an repair. I basically followed two reports on the riovolution forums: one to open the Carbon and a second for repairing the wheel. Those topics where a great help and my player works again, though it doesn't look like new anymore.
Repairing the wheel is very simple but opening the device is really hard. I won't repeat all steps mentioned in the links above here, instead I'll just post a few pictures here. Click them to get some detailed info.
Update: the forum I linked to does no longer exist. Some textual info on how to open and repair the Rio Carbon can still be found here.