Ecosys M6535cidn yellow background and black shadowing

[Arkynsaw]

I have the parts and service info , 1st time servicing this machine , disassembled to check yellow issue . Removed toners , primary transfer unit yellow drum and yellow developer unit . Cleaned the slit lens for the yellow laser as it was dirty . The only part that was questionable was the yellow drum unit , it looked like the drum was not cleaning proper , looked like a bad drum blade symptom . Reassembled and tested , looked ok on B/W only pages , but on color pages the yellow background was still showing . Unit may still be under warranty customer thinks , less than 2 years old and has about 60 k pages on it . They called back and reported the black shadowing after I was there , had not happened for me . I have report pages if more info is needed . Thanks in advance , Ark .

[copiertec]

How many Pages on it? Is past maintenance cycle? You can swap drum units and see if it follows to the color you swapped it to. If it follows, drum unit is bad, if not developing unit may be bad. Also, if they purchased the MFP through your company and it is not older than 3 years or past maintenance... it should be covered under warranty.

[blackcat4866]

You could have a black or yellow drum cleaning issue, but that's usually fairly obvious to diagnose.

More likely you've got one or more bad developing units. Image samples would be nice. =^..^=

[Santander]

A color background could also be caused by a short to the charge grid. Had one last year on a color printer, that was producing a yellow background and had changed the drum, developer with no success. By accident I noticed a tiny spark on the metal strip used to provide the voltage to the grid. Toner dusting had created a path to ground for the voltage creating the background. Vacuumed the toner dust off corrected the problem. You may have a similar problem.

[sparkycivic]

I've been finding that the transfer belt cleaning screw isn't very effective, and reminds me a lot of the issues that the FS-c8525 issues with same.
when the trans belt starts puking junk, it gets into the yellow drum cleaning blade because that's the next device along the path.