Does it not attempt to, or go through the motions without coming up with a sheet?
I had a Desket 550C go the second way.
The weak points are the spring bed in the paper deck, and the rollers.
Some models had bad rubber in the the rollers and needed an abrasive kit to roughen them - but I think that was earlier.
One trick, apparently, is to wipe the rollers with neat washing up liquid, which both cleans them and the residue makes them sticky.
