Mamiya 645 Pro winding crank slipping .. film back or body?

[lacy_dillard]

I picked up a 120 film back on eBay and finally got my 645 Pro body

and finder from KEH today. I suspected a film spacing problem so I

ran an old roll of film through the back while tracing each frame

through the body with the shutter on B. No spacing problems, but the

advance is very very rough. Not only it is difficult to turn the

crank, but it seems to snap as it reaches the end of the advance and

sometimes slips and rotates past that point. Is this a film back

problem? The body looks great (Excellent + condition) and I trust

KEH.com far more than I trust the eBay seller (I was already surprised

by the physical condition of the magazine). Anyone have this issue

before?

[chauncey_walden]

Lacy, when placing the insert into the back did you do it positively enough to get a click? Sometimes you have to jiggle the handle a little.

[lacy_dillard]

Thanks, Chauncey, but both sides of the insert click when inserting (I've been practicing so that I don't ruin any film :). Could it have more to do with the gears in the magazine?

[peter_obaldo]

Sounds like a dirty film spool to me. Double check that the rollers are free of dirt.

[lacy_dillard]

I don't know why I didn't think of this before, but I cocked the shutter without the film-back on. I'm amazed! I read information on the Mamiya 645 cameras for weeks and never found anything about the advance/cocking sounding awful. Is this unusual? It's rough and there's a jarring snap at the end of the turn. I also ran another roll of film through it but this time with a Fuji "easy loading" spool on the take-up side. I got a spacing irregularity again. I get 15 frames and the breaks are even but one skipped up 1.5 inches. I've cleaned every roller I can get to and everything I can see looks clean ..

[lacy_dillard]

If needed, I can record and post an MP3 of this awful noise, haha! I can't believe that such a terrible sound could be normal, but it's always possible .. I feel like I'm damaging the camera everytime I cock the shutter.