I finally had a chance to do some more in depth diagnostic work. So far as I can tell the paper sensor flipper switch is dead (it's called an out of paper switch in the manual, OOPS). I removed it and don't get any response when I ohm out the connections while flipping it down. I've ordered a new one from Partsphere. I wanted to be sure that the roller mechanism was OK, there's a motor and a driver board that could have been bad, so I found a check in the diagnostic menu that it went through OK. I could see and hear the rollers running back and forth during the tests. I had hoped that I could short out the OOPS wires on the printer to fool it into thinking it has paper but the connector is impossible to get to unless the printer is jacked up.
If this doesn't work I'll either be in the market for a new 24" printer or will wait, maybe until next year, for new models to come out. In the mean time I've been putting my 4880 Epson to use which is good for it as it sits largely idle otherwise..