was looking over this and agree w/ Hansoon dev, drum, hopper, need to be completely cleaned out very messy job. also you should change drum &blade as these will most likely be damaged in the proses. dev can be dumped into good plastic trash bag then vacuum out dev unit w/good vacuum. do not get this unit wet in any way!!! add dev powder, reassemble drum unit .drum is light sensitive do not leave exposed to long. when finished run dev calibration may take several minutes . good luck