Bronica GS-1 film back repair

Two of my GS-1 120 film backs (6x7cm) would not break the shutter firing circuit when the dark slide was inserted. The camera fired with the dark slide inserted and produced unexposed film. This problem was solved by extending the length of the pin that is actuated by the slide. A small round piece of card stock was inserted on top of the pin and under the actuating lever. That is enough length to to the job without damaging the camera. The first repair was difficult. The second was a snap.