RZ67 slipping-back or camera?

My used RZ67 makes some negs overlap (one frame over the other). I have two backs so not sure if its the back thats
problem or the camera?

I have had problems using original RZ 'Pro' backs on a RZ 'Pro II' body. I don't do that anymore.
RZ 'Pro II' bodies and RZ 'Pro II' backs make for the best mechanical [drive] interface.

The problem seems to be with the original RZ 'Pro' backs being a four (4) prong drive,
and the newer RZ 'Pro II's,' having a two (2) prong drive.
(I'm calling the interface 'prongs,' because I'm not sure what else to call these drive dogs/tabs/teeth).

I haven't had problems using original RZ 'Pro' backs on original RZ 'Pro' bodies.
Also, no problems using RZ 'Pro II' backs on original RZ 'Pro' bodies.

The newer film backs can go 'backwards' to an older body, but I don't bring the older backs, 'forward.'

Most of my backs are now the newer 'Pro II' variety.
RZ 'Pro II' backs are better, all around, with the light trap seal system, as opposed to foam seals.

Ez,
Having said all of this, what combination of back(s)-to-body do you have?
When was the last time your back(s) and body had a CLA?
Also, what brand/type of film are you noticing the problem with, the most?
Problems more at beginning of the roll, or more toward the end of a roll?

The bad news. If your problem is not isolated to the backs, there are times that gearing
inside the camera body can be the problem. This can be easily addressed during a CLA.

Marc

PS: Not addressing your existing problem, but in the future, remember that RZ Pro inserts
will only mate with RZ Pro housings, and Pro II inserts only with Pro II housings.
The only commonality is the dark slides.

The back is responsible for frame spacing and it tells the camera that it is fully wound when it thinks it's fully wound. While you can get slippage between body and back, the double-exposure prevention thingo should stop you releasing the body again before the back is fully wound; you'd have to push the crank again or wind the back manually before getting anywhere.

The back needs servicing or replacing.

I have the same problem. It's the film back not the camera. I think there's a nylon gear that got stripped.

Thanks! i bought one of the backs used on ebay but not sure which one now. I have them marked now
so next time i shoot i can figure out which one is slipping. Glad its not the camera! Its the older regualr RZ not the Pro II.

You can figure it out easily. The rewind knob on top of the back should only go one direction. With a strip gear, there's a spot where you can turn and the knob will go the other way slightly. That's the spot with the missing teeth in the gear. I think the gear in the back keeps the film taut so the exposed film doesn't go in reverse. That possibly causes uneven frames. You can buy new RZ backs on eBay for cheap now. Just avoid those useless RZ 220 backs. I don't think they make 220 film anymore.

You can use a 220 back with 120 film though... and they're cheap!

There is still 220 film but it costs more per frame than 120

thanks! i actually bought a 220 back for it on ebay, havent tried it yet. I'll put some 120 in there and check all three.

The only real issue I have with using both 120 and 220 films in a 220 back is remembering what length of film is in the camera.