You have a bad drum/developer cartridge.
Yesterday, after a Paper Jam, we suddenly started to receive an Error "Deve Motor Fail" with the Chain Link 393-320-00.
I tried to enter Diagnostic Mode (held 0, pressed Start, logged in with "6789") and this worked, but I am unable to access the menu I need - when I hit "Machine Status" it will not let me advance. I believe there is a way to clear the faults in this area.
I've restarted & unplugged the machine a few times; I've reseated the drums (though not sure if I should have done it differently).
Presently, I'm not sure how to troubleshoot this or workaround it. Any advice would be greatly appreciated...