Hi all! I just picked up an immaculate used F100 for a very nice price from a gent via 'craigsfist'. Looks as new, and he said it had maybe seen 4 rolls of film in its life. BUT... after running 3 rolls through the camera, I am getting a few overlapping frames and odd frame spacing in each roll. Batteries are fresh. It is an early version with the triangular shaped plastic rewind fork.... not the updated square-ish (though still plastic) rewind fork, and I am wondering if that may be the culprit? It isn't broken... but it is less springy (when pushed into the camera) and upon close inspection looks a very little bit worn looking (we're talking slightly here) than the rewind fork on my last F100 which this camera was to replace. Looks as if it should still function... So I am wondering what might cause the few overlapping frames and funky spacing? Bad film advance gearing/mechanism? Any ideas? Thanks!