Ah, finally saw the last post. SQAi backs are pretty easy to change the seals in and you can order the seal material fairly cheaply from Tamron. If you take it to a repair shop expect to pay an exhorbitant rate for this work. Peachtree Camera wanted to charge me $80 to do this, thier excuse was the seals were expensive. I got enough from Tamron to do all eight of my backs for $20. Heh!
Also if the film is not being wound tight enough in the back you can bend the little tensioner springs out a bit and will fix that.