what causes dark background on copies, but scans and prints look fine?

[rockdude]

Can you tell us if thier is "ANY" difference when you make copies on the glass as oppsed to the ADF?

If you make a copy of a "BLANK" white page both on the ADF and on the glass, is thier any difference in the density of the gray?

If you make 25 copies of a "BLANK" white page both on the glass and with the ADF, is thier any differnece from the first to the last copy?

Let us know?

[sbtiti]

There is a difference between the ADF copies and the flatbed copies, but I don't see a difference between first and last pages. I will attach a photo with 3 stacks of pages, the left is flatbed, the middle from ADF and the right from a print job. The print job is total white (printed a blank page) and the other two have darker shading on bottom 1/3 of page. The ADF one has strips of shading going vertical through the page as well as the more grey on the bottom third.

Not sure what the problem is, but the photo will not upload. I hope the explanation above will be good enough.
Thanks for your help. I may need to make a lower res. photo & see if it will upload.

[sbtiti]

Another try at attaching PIX

[sbtiti]

It has been a few days since my last update and maybe you all have given up on other ideas to help. I found a used main logic board on ebay so decided to give that a try. This unit has been off for a long time, but after installing the new (used) board it produced nothing but a dark page in all forms of printing. I put the original board back in and at first it had the same issue but after a few test pages it came back to the original symptoms as in the title of this post. I guess I'm at a loss of what to try next, unless I can get another 3635 to swap parts with.