I just got in a used Bronica SQ-A. I was testing it out and reading over the manual while going over the buttons and switches. Everything seemed to be working fine. Then all of the sudden I can't trip the shutter. The mirror lock-up switch was stuck in "N" but the mirror was locked up. I could press the shutter button and there was pressure on it but it wouldn't release. I finally got the mirror lock switch to move but still couldn't fire the shutter.I tried loading the back with film and that didn't help either. Anyone go any ideas?