I've have the 2 latest style A12 magazines (the ones with the built in slide holder 30212 and the model 30147) and can load them fine but I just acquired a older version A12 and have a question. Usually I load the film, lock the cartridge into the back and wind the lever until it doesn't permit anymore winding. The number "1" shows in the frame counter window. With this older back, when I wind, there is no apparent point where it "brakes." I see on the frame window "0" at first, then as I wind the film, eventually "1" appears. If I don't stop winding but continue, it goes to "2," "3," etc. I assume I am going too far. Do I stop when "1" clicks into the window or is there something wrong with the back that needs servicing as it doesn't automatically brake when it reaches "1?"