Hi all,

Ive a low used, good condition C850 with C7101 on it & it's driving me mad!

Ive had the Engine board checked over for issue's and all is fine, ive also removed and cleaned the clutch on the black dev unit and it's still firing the code. I have even swapped out the dev unit with another and still the code lives on...

Firmware is all up to date, not sure what's left before the old girl goes to copier grave yard in the sky...

I guess you have now a low used, not so good condition C850 with C7101 on it & it's driving you

Have you checked the Black toner feed assy? That is the tube that carries the toner fron the hopper to the dv unit. It may be clogged or not turning. Also check connector YC11 on engine pcb this is a black toner empty sensor. There is an emitter and an receiver. Good luck.