The Supermatic came in 3 basic versions, the no flash sync called Supermatic, The flash bulb and electronic flash synced called Flash Supermatic, and the electronic flash synced called Supermatic X. The Flash Supermatic is the most difficult to service and the Supermatic the easiest. On a scale of 1 to 10 of increasing difficulty the Supermatics are a 6.
Originally Posted by Cybertrash
The service manual for the Supermatic with 127mm Ektar is (was) readily available on line from several manual retailers such as http://craigcamera.com/ item 90518 under reprinted service manuals.
The blades opening unevenly says that the operating pin holes in the blades or controller are worn and the related blades are sticking. Continuing to use in this condition will result in a non working parts shutter.
flash supermatic disassembled.jpg
Service it or have it serviced soon.