I recently acquired a pristine Canon New F1 from 1989. Having seen such little use over its life, the grease from the mechanical parts congealed where they sat. I had this sent to a very experienced repairman, and he cleaned up the internals beautifully. As far as I'm aware, he performed a detail strip of the entire body.
However, I've noticed a strange quirk which was present before and after I sent it for repairs. When turning the shutter dial from 1/30th to 1/15th, the transition is not a firm click as with the other speeds. Rather, it feels rough and course, almost as if something were sticking out of that particular gear and scraping whatever moves across it. That is, however, just how it feels to my inexperienced hand. I really don't know what it is.
Furthermore, I can leave the dial somewhat locked at mid-turn between 30 and 15, which cannot be done on any of the other dials.
I know for a fact that this isn't the transition from the mechanical shutter to the electronic shutter, because that would start from 1/125 to 1/60. This is well within the electronic range.
Others have told me that this probably isn't worth worrying about as the camera still functions fine at all speeds, and it only affects this one transition. But, being the priciest film camera in my collection by a good margin, I don't want to leave it to chance. I'd just like to know whats going on, and whether its worth sending the thing back in for repairs. I'm only concerned if it harms the function of my camera; I don't otherwise mind it.