Hi I realize this is an old thread but maybe you or someone can help me. I'm having the exact problem you describe - I have a kowa super 66 that I bought and shot a few rolls through fine but now, after swapping the lenses, is jammed. I know lens has to be cocked prior to putting it on. As far as I can tell the body is cocked, lens is cocked, mirror is down but shutter button will not activate the shutter. See picture for reference. I'm not sure what you mean by "pull gently but firmly until the mechanism comes into top position." When you say "pull" do you mean "turn"? Shouldn't the body already be cocked if it allowed you to take the lens off? As far as I can tell the mechanism is in the top position. Any help would be appreciated.
