My new-to-me Bronica ETR came today in the mail. Pretty much meets description, except that it seems broken. I just put a new battery in it and a fresh load of Velvia. Problem is that the shutter won't seem to cock. Film will advance but not stop--I rolled through an entire roll without the shutter cocking. Took the film out and put it back through to roll it back onto the orignal spool, but it jammed up half-way through. Any ideas would be greatly appreciated.