I've got a Nikkormat FT2 here that had a bad screen, so I swapped an FTN screen from a junk body into it. But the focus is off compared to all my other Nikons and Nikkormats. I don't know which direction off hand, but it's about 1/8 inch off in it's turn up near infinity. I don't recall the screen being spring-loaded requiring collimation. I believe I remember the screen dropping in onto a hard stop, like the F and F2's, and not a spring loaded affair requiring calibration. So, why is the focus off? Thank you.