I have a Hitachi DDC 52N with about 2,265,xxx on it and am getting backgrounding and lines. It gradually gets worse the more you run through it. I have replaced both charge units, eventually swapped out the whole process section, and have swapped out several circuit boards. I don't rememeber the exact names of the boards I've replaced, but can describe them. (pwb C, O, main control, for sure) There is a slight background and banding that will start to show up after about 100 copies. The bands are about a half-inch thick, with about 6-8 of them running lead edge to trail edge on a 8 1/2 x 11. We have about 4 of these left in the field with no real support on them. I know the Konica Minolta (DI)620's are pretty much the same machine. Any help would be appreciated!