SL66
When I purchased an SL66 it arrived with the mirror up, and the whole camera frozen, including the back. I shipped my camera to Jürgen Kuschnik in Germany of Dead Link Removed. He repaired my camera to perfect function, and I had my camera back within about three weeks including shipping time. He is very familiar with this camera, and has a good supply of parts. He is fantastic about keeping you advised about what is going on with your camera.
E-mail him, of course, to discuss your situation and before mailing your camera.
If you can arrange to pay in advance, it will probably speed up the return of your camera to you.
When the camera is operating properly, it is imperative to wind the crank to advance the film and then block the crank in the reverse direction before doing just about anything, including removing or attaching the back, lens, pressing the shutter button, etc. Also, with the back removed