I picked up two old 90mm lenses in hopes of getting at least one to work.
The one with the operable shutter has the pinprick holes...and a slightly fungus'ed rear lens. I have already cured that with a 50/50 mix of Ammonia and Hydrogen Peroxide. I really didn't want to do a complete tear down piece by piece on the shutter, as I usually take out the lenses and the body and then soak the whole shutter in White Gas (Coleman lantern fuel), and then after a 15 minute soak, I turn on the Ultrasonic cleaner and let that run for 5 minutes. Usually whatever is causing the jam, is jarred loose, like dirt and grime and then I completely rinse it in fresh white gas, and then when it dries overnight I oil the spindles of the gears. That's about it. Runs great after that. I clean and reinstall the elements and rings and it runs like a champ.
The other lens has a jammed shutter, so I will in fact tear it down and make it a parts shutter. Both lenses are old enough (1970-72) that they have Type "a" blades, so it should hopefully be a quick repair.
This is not for my camera, it's for a friend. I want to make sure she has no problems, and the lens is in top shape. $40 for both lenses shipped. It has been fun. Thanks for the replies, and the laughs. It really is microsurgery. My guess is the holes were caused by corrosion. I removed the rust from the blade with a fiberglass pen. I love that thing..
So it's either try to patch it or replace it. I might try both. replace it, and then do some practicing on what method works. The pin holes are at almost the base of the blade, so not sure about centrifugal "g"'s and it coming loose. If I can patch the blade, I will scrape off the rest of the paint around it, and then try a micro brush with the smallest amount of JB weld... These holes are tiny. I bet it will work. Worst case scenario I'm out $40. Best case scenario it works and I gain some knowledge about the Mamiya Shutter That and couple more gray hairs on my head. The JB weld is made for metal, but I will have to use the slightest mixed measure. plus it's black/gray colored. the rest of the paint that I will take off I can fix with dye, or my cheap alternative of a permanent black magic marker.
I love a good challenge.