Customer had labels stuck on primary transfer. Able to get working OK but had small gouge in it where customer tried to get label with fingernail. Replaced with new unit.
Replaced Black drum and MC kit as label on drum also. (Had 77K on the black meter). Did sims for new belt and for drum change. Ran 100 test copies -all OK.
4 days later got call saying copies from front to back-(not lead to trail) having the back half very faded (evenly so)...~ back 1/2 all faded the same level (barely readable).
Swapped Black Process Unit with Cyan Drum unit and still same issue( still back half faded).
Also Note, if run one color such as cyan or green prints then print OK. Other misc notes:Cleaned LSU cover glass also with drum out, lifted cover and viewed LSU cover glass with flashlight.
Additionally, prints are then same whether on platen,scan or internal test prints. Just in case - changed out black developer and recalib. with sim. settled at 128. Also to rule out various misc, also checked toner motor.
Thought maybe cam on belt acting up. Since still had old belt unit so put it back in. THEN entire page printed faded??? So put the (new) belt back in, then again only back to only 1/2 faded. (and did screw belt into place)
Checked rear contacts etc. Then once again, put back in old belt and again full page faded. Checked the machine mounting guides for belt - they are OK. Swapped back to new belt and again 1/2 faded. Belts is seating on frame as should be.
This really has all 3 of our techs stumped. NEED HELP. customer is a large 40 person office and uses this for their only incoming fax machine (they get about 10 important faxes per hour) Also they print ledger color maps etc.& without a back up machine for ledger prints) Thanks for assistance.