I have an OM2n and a Winder 2. The Winder works at least 95% of the time, but usually once or twice per roll, it will fail to fire. Then I have to press the proper shutter release anyway, and hopefully the picture wasn't missed. When it fails to work, it really fails, and mashing the button down repeatedly doesn't do anything. But then later it will start working and work fine from then on....for a few dozen shots. The way I see it can either be internal., or it could be the contacts on the bottom of the camera, or the button itself. The contacts on the bottom of the camera appear clean. Is there something special I could use on them?