I recently bought a Hasselblad 501C with two A12 backs. The body, lens, and one back are in great condition but the second back seems to have an issue with sticking. As far as I can tell, there is a pressure spring next to the take-up reel, which is designed to keep the film tight on the plastic spool. In my back, however, the spring seems to be bent somehow, in such a way that after 9 or 10 exposures, the pressure it puts on the take-up spool is too great to continue to wind the camera (as evident in the second picture, the spring is already pushing against the empty spool). Since the other back I have is of a different design (it has spring-loaded buttons instead), I have no way of knowing what "normal" should look like regarding the spring. I think that I have narrowed down the culprit, but I wanted to see if anyone had any ideas about how much this would cost to get fixed, or whether there is something simple i can do myself? The seller from whom I bought it seems very willing to take care of any repairs I may need, but if this is relatively inexpensive, I would rather save us both the trouble and have it done locally. Thanks in advance!