Also: Sadly, some of the e-unit replacement parts that have been on the market over the past few years are not made correctly. Some of the problems I've seen include:
drum contacts mis-aligned.
E-unit fingers too long
E-unit fingers fiber board too thick to fit into the slots in the frame.
If the motor is buzzing, the eunit fingers are making contact. If they are not, the motor will not buzz.
I guess that certain e-unit fingers could be shorted to the e-unit frame.
