To get back on track: I have been using my two F3s since their purchase in the late l970s. I have not encountered any problems with the cameras. The 105mm Nikkor needed attention on the auto/iris which was attended to after twenty years hard use - free of charge!
I do however, get the cameras serviced by Nikon every two years or so.
I still think they are the best cameras in their class, and have justification to be just a tad biased.