Bizhub C500 - Error Code 29-07

The machine have new developer Y, and a New original Drum unit too, run OK all process Adjustment, automatic developer charge, L detect initial autoADJ, but after the developing unit dont make the developer charge well. The magnetic roll does not charge developer and when the machine start it shows error code SC29-07. we check corona unit, drum and everything its ok, the developing unit has already 300K prints in her counter. Toner Y level its ok! when run autogamma ADJ shows the same error SC-29-07

 

Well, the Code is for toner density, which I assume you knew since you mentioned servicing the developer and drum.
Are you certain the magnetic roller is not functioning? it could be the density sensor or gamma sensor that is not working properly.

IF it is the roller, then you must look into the motors and boards associated with it.
It could also be a power supply or faulty developer. Xerox used to send us bad drums and developer all the time, I've never had an issue with KM though.