I recently bought a Nikon F100 off of KEH. It's a beautiful camera, but upon inspection I noticed that the internal diopter adjustment is off track or not engaging. The adjustment screw rotates freely when pulled out and does not change the diopter setting. It also rattles back and forth slightly. The digital readout in the viewfinder is OOF, but the camera focuses properly (Duh, but just in case you were wondering). The camera was listed as an EX without any information about a broken diopter so I could exchange it, but I was planning on taking it with me to Colorado on Tuesday. Proper judgement says to just return it, but I'm stubborn. I'm wondering if anyone has had experience with a repair of this issue. I'd be willing to put up with the problem until I can fix it myself or pay to have it fixed if it is economical. So, my questions are: How much of a PITA was it to fix the diopter yourself or how much did it cost you to have someone else do it? Also does anyone have a PDF of the official repair manual they would be willing to e-mail me?