Omega D2 aligning lamp

I have an Omega D2 which I have aligned in the past, and lately, when I make a proof sheet, the right hand side is very light. I redid all of the alignments, and now I think the light source is not centered with the negative carrier. I know how to move the lens stage back, but still. At first I thought it was bad paper, but now I don't think so. Any clues, thanks, I appreciate it.