Bronica EC Film Back

Won a EC back from Japan, looked almost unused but it will not advance film. Has anyone ever looked under the hood or know where to find a repair manual. The seller has made a offer of sale price less shipping but if unrepairable I do not need anymore paper weights My camera works fine with the back I have, I tinkered with both backs several hours to no avail. With the new back loaded with film the shutter will cock but it does not go through the film advance from start to first shot of the roll. And the camera will recharge the shutter each time without film advancing.

Any advice or suggestions would be most welcome, I need to make a decision soon on keeping or returning the back. Thanks

I've had one open before, fairly easy but you have to remove various pieces of leatherette (and rubber, on the bottom) to get at all the screws. The most difficult screw is under the small, circular piece of leatherette on the winding knob. What's tricky is that, because it's fixing a knob that's designed to go anti-clockwise, the screw is opposite thread so you'll need to turn it the opposite way to what you'd think. It sounds like the back thinks it's in multi exposure mode (which is selected by twisting the dial on the back to 'D') so it's probably quite a simple fix. Probably.

Thank you, I will keep the back and see if I can make the fix. Will advice on out come, but I do have several cameras in pieces that I am working on