We have a WorkCentre 3210 that gives the Jam 0 error message when trying to print/copy from Tray 1. It will print from the bypass. When it gives ther error, no paper is to be found anywhere in the system except in the tray. It looks as though it didn't manage to pull a sheet out of the tray.
I've tried swapping out the paper tray and the feed roller from an identical, functional unit. I also tried changing the tonner/drum cartridge. No change. I've looked at the paper feed sensor but can't see anything visibly wrong with it.
The things that the service manual suggests could be the problem would also seem to cause issues with printing from the bypass so I'm at a loss as to what to try next.