Cause

Drum motor abnormality

Resolution

First power off the printer, leave the machine off for 10 minutes, power back on.
If problem persists turn main power switch ON while pressing the Utility/Counter key. Keep holding it till the Service Menu appears, go to [Service Mode]-[02 Process Adjustment]-[Gamma Automatic Adjustment] run this procedure.
Exit out of service mode.
If problem reoccurs then call 01-5676000 to log a service all.