Peters: I went to National Camera Repair School in Denver after I got out of the Navy. I had to do several CLA's of cameras and had the equipment to check the shutter speeds and curtain travel times and everything else that was needed. I remember taking a Nikon F all the way down once and when I put it back together the shutter was off. I took it all down again and when I put it back, the same thing happened. I asked my teacher and he said to take it all down again and clean it like crazy. I did and it worked perfectly. All it takes is a little piece of crud and you are out of luck. We had shutter testers which were really ocilliscopes made for that. A focal plane shutter can be a puzzle to get the curtains balanced without a tester. Taking down a camera also sometimes can mean a spring that flys off to the Twilight Zone, and a ball bearing that disappears into the unknown. If you do want to try it though, you can test a shutter with a phonograph record player with a marker to determine how far the marker traveled as it was photographed. You will have to do the math. Ofcourse if your record player is off, so will be your camera. NatCam went out of business years ago, and most of the teachers are now gone. Phil Zimmerman was with C&C training which you can find on the net. A professional tester costs about $2-3000, but you can get the shutter checkers that only check to see if your speed is correct for $100-$200 and they are handheld. (If they are still made.) For the old leaf shutters, I didn't tell you this but you can sometimes dump the whole thing into a cleaning solution and blow dry it out and it will work. (Remember I didn't tell you that.) If you just want to see if you can get an old camera to work, go for it, but I would not do it on any camera that I wanted to use to shoot a wedding. Ric.