I have an 8030 that has full black background on the complete page except the lead edge white void and trail edge. You can see the full text and it looks ok. It is on the copy and internal prints. 1 mill. on machine and 100,000 since p.m. I have swapped parts with another machine for troubleshooting with no luck. so far i have swapped the drum,charge corona,pre-trans corona,dev. unit and transport unit.I have cleaned the drum ground in the front and shaft.Adj.drum potential and charge. No help.I plan to try the drum potential sensor later this week. Any ideas?

That's exactly what the copies look like when the Drum Potential sensor goes bad on a 5530...about the right meter counts too...I think you've got the answer as soon as you change it. -Cope

Yes. the 5530 was a common thing for it. But i have never had to do it on an 8030,6030. Most often on the 5530 you could run sim. 100 and get the copies back for a day or two. I tried this several times on the 8030 with no luck.

Look at the copy, is it background or very close lines.

No. full shadow with text in the background. Already tried drum.What area were you shooting for about the lines. I could check that too. thanks

When I had the bad lazer harness. I thought I had background also until I looked at the copy closer.Then I seen the lines

the white latch on the back of the image section that holds the main charger in place, that is not locking the lock rounds off replace that locker and it will work fine

Dark background on all prints has been the pre-transfer corona a couple of times for me. I just had to take it out, clean, and get seated back into place better.

After replacing complete process unit from another machine with no luck. Rep.drum pot. sensor and board, and HV power supply for charge and transfer no help.Called hotline. cleaned drum ground tabs in rear and front.No help. It had 5 drum pot. sensor 1 errors in the service call counts. The last ditch effort was to try a laser unit. Nothing pointed to this as the problem to me and also hotline. No laser c- codes listed.The first copy was perfect. It fixed it right away.I guess with the laser unit not working properly the DP sensor got bad readings causing the codes? I don`t know, it is just fixed. It is nice to have a junk machine for parts.

Usually this is caused by noise/loose LSU connector where it plugs into the LSU itself. The best temporary fix is to simply re-seat the connector and then order the updated wiring harness that runs from the main board to the LSU. The new harness has tighter female ends. There is a Q&A report on KMA referencing this, so I'm surprised they didn't let you know. I'd be willing to bet the laser itself was fine and eventually the problem will return. How old is this machine?