Gestetner ds c428/ricoh 3228c sc 440-02 error code
initially the machine was displaying yellow developer unit disengaged swapped the developer unit with cyan to verify unit was defective, then sc440-02 code appeared, replaced yellow developer unit with new one disengaged yellow developer unit message disapeared but error code sc 440-02 remains disasembled drum motor drive seemed ok , checked in output modes slow speed ok, medium runs for a few seconds then stops, and fast also runs only for a few seconds not sure if this is normal. all drums seem to be turning ok and drum speed color sensor was swapped with black sensor problem remains.