Hasselblad A12 Back: Problem?

[photomat-]

Hi,

Just finished a roll of film and after I wound on after the last frame, it didn't seem to wind on far enough. I used the winder on the body and it did it's usual cocking of the shutter/mirror. I then used the winder on the film back and it didn't go any further than where it was. I put the dark slide in and removed the back, no difference. At this point, I went into a dark room and opened the back. Sure enough, the last of the paper was still on the lower spool. I managed to fumble around in the dark and get the spools off with the film intact and taped down tidily.

What could have caused this? This is the third roll of film that I shot and had no such problems with the other two. Mid roll, I had a problem with an extension tube that resulted in me having to take the lens off with the body still cocked and manually cocking the lens. I can't see how that would be a factor though.

Thanks for any input or thoughts on this.

Cheers,
Matt

 

[Q.G.]

The tube and lens have nothing to do with it.

Something inside the back is not the way it should be.
A blocking magazine wind crank points to a blocked mechanism inside the back, either because something has gotten 'out of synch' or out of place, or becaus ethe wind crank blocking mechanism (a rather 'tall' description of a simple thing) kicked in when it should not have.
Which itself (the latter) could either be due to the former, or to old grease gumming things up.