I purchased my first winder for my RZ67 a couple of years ago. I loaded it with batteries and started it but it would not advance the film. I heard a lot of gears turning but no film advance. I thought that the batteries were weak and I was pretty sure that I didn't buy a broken winder. A year later I put in new batteries and still nothing. I thought that the grocery store sold me faulty batteries but then I thought, "Naaaah. How often does that happen?" Finally last week I decided it was time to start looking for another one on e**y. I decided to give it one quick try but again it didn't work so I decided to take it off and put it back on and as I'm examining the contacts I realized that there's a door on the bottom of the camera that protects the gears when you're not using a winder! Silly me! I haven't tried it yet but I'm sure that it works.