My 3D printer stopped working just before Christmas and it took me a while to diagnose the root cause. It would get hot and extrude but not print when I tried a known-good file. A blocked nozzle was the original problem but very cold ambient temperatures and slipping feed drive had me disassembling the head numerous times. New nozzle and throat bolt (to be sure) and careful re-assembly had it back up and running by New Years Day (I know how to party!). Let the printing (re-)commence!