Cs-2114 all dark copies

Question

HelloThanks for your suggestion. I restarted the copier and copied normally, exc. for flashing message. Ruined my whole day yesterday thinking I screwed it up. I don't have a tech manual to follow any instructions. Do you have one for this copier? I'd be glad to pay for a xerox copy. I ordered some developer. Do you think if I put in new developer, the flashing "replace unit" light will go off??