Mamiya C330 wind on problem

[EWPhoto]

I just recenty got a Mamiya C330 professional (not and S or F) I put one roll of Kodak Portra through it but after i shot the first frame it wound on to frame 4, frame 2 was exposed (I may have hit the black plastic shutter release on the side while advancing the film but I didn't t think i did) and frame 3 was unexposed and completely clear.
I have fired the camera several times since without film and it seems to wind on twice every now and then, maybe once or twice per 12 shots.

Any ideas what might be the cause of this or if there is something i could do to fix it myself? I don't know of anyone who would repair/service these in Ireland or UK.
Thanks Eamon

 

[Mackinaw]

This may or may not explain your problem. If you look in the upper film chamber, you see a gear that is on an angled chrome shaft. The gear is supposed to contact the roll of film as it advances through the camera. If it doesn’t, you can get advance and spacing problems.

Jim B.

 

[EWPhoto]

Thanks, that gear is in contact with the film alright and is in contact with an empty spool up top when i have shot it without film. I guess ill try another couple of rolls and see if i get any clear/unexposed frames.

 

[Mackinaw]

Also be sure the gear isn't slipping. That too, can cause advance problems.

Jim B.

 

[mike rosenlof]

The later Mamiya TLRs have a feature that if the shutter release (on the body) is held down while winding, it doesn't stop, it just keeps on winding. It makes it easy to finish off a partial roll if it has to go in the soup right away. If you're not holding down the release, there might be a problem with the mechanics behind this feature.