Konica Minolta 6500 Pro Image Ghosting Issue

We recently had some service work done on our 6500 by an authorized Konica Minolta Service provider for another reason but we now have Ghosting on about 50% of our work. When ever we have a heavy black line (illustration of a floor plan) with 4-color next to it you will see a ghost image or the black in the 4-color if the color is a lighter shade "falls within specs'". It was never there before the service work was done.
Also color registration is now off. On a 12 x 18 sheet all text weight papers register color perfectly. On cover weight papers (80# Cover and heavier) the first 1/3 of the lead edge color is out of register. So if we are running a job 6-up on an 12 x 18 cover weight sheet we can only use the last 2/3 of the sheet. Again "falls into spec's". Any Thoughts would be appreciated.

 

You need a new drum, we have the same issue with our xerox machine, our km 6500 doesn't have this issue but did and a new drum was the answer, hope this helps.