Archive for June, 2020

Fixing Kyocera fs-6021dn errors 7401 7402 7403 and 7404

Thursday, June 4th, 2020

At the office, we had a cheap Kyocera fs-6021dn. After a few years of use, the printer finally gave up with error 7403. Looking at the service manual, the error description is: Developing unit M noninstalling error No density detection signal is output from toner sensor M in developing unit M. Possible causes:  – Defective […]