[Error Code] C7301 error on a taskalfa 6550 ci

[mac777]

Has anyone ever had C7301 (toner hopper motor,sensor error K),I have changed the hopper motor and sensor
and both are working.And just to be sure i swapped both motor and sensor with the magenta hopper,but the error still returns.The firmware is up to date.
I have also reset sim 906.
Any Ideas i would be very grateful.
mac777.

[mac777]

Re: C7301 error on a taskalfa 6550 ci

Answer to my own question,one of the black developer drive gears had cracked and spilt,replaced developer assy+set up machine now o.k.
Troubleshooting in the manual seems a bit vague,plus the version of the SM i have (rev4) shows the toner hopper motor in the rear of the the machine when its really in the front.