My lab's aging LaserJet 1200 recently started failing in an interesting fashion. It would print a page nicely, but then attempt to feed a second page before the first had finished, leading to a jam. Some googling lead me to this page which indicated that the feed solenoid was sticking. After a failed attempt to clean gunk off of the feed solenoid arm (and failing to find anything else wrong, I wrapped the feed solenoid arm in scotch tape and attempted again. Viola, a printer working once again.