645 Super skipping frames.

[adam_koch]

<p>I am having a strange problem with my 645 Super, I'll shoot a roll of 120 and when I go to develop the roll I end up with large portions of the roll completely blank however the amount of frames skipped seems to vary between 2 - 6 per roll (see image below). <br /> <br /> I checked all the gears in the back to see if any of the teeth were worn or broken and all looks well, when I go to forward the roll the winder arm seems to slip sometimes I have tried to wind slower and with even tension but it doesn't help.<br /> <br /> Any ideas? Maybe I just need a new back?<br /> <br /> Thanks in advance, Adam.<br>

<img src="http://img134.imageshack.us/img134/2552/mamiya.jpg" alt="" /></p>

[cametacamera]

<p>one question, two suggestions:<br>

are you shooting 120 film and is your insert for 220?<br>

If not, try another back or another insert.<br>

Have fun!</p>

[rodeo_joe1]

<p>None of those frames look properly spaced, and I've never come across this problem with a Mamiya 645 before. The frame spacing is usually bang on. Anyway, here's a few things to check:</p>

<p>Have a look at the condition of the rubber on the roller that contacts the film in your insert and check for stripped teeth on the little gear at the other end of the spindle. Also check that the gears between the back and the camera body are meshing properly. Check the tensioning springs of the insert (the leaf spring rollers that press on the back of the film), these are prone to getting bent out of shape. And try a different insert before writing off the whole back.</p>

[rodeo_joe1]

<p>Just one more thing. You are lining the film up properly when you load the insert, aren't you? Because I've just spotted what looks like part of a frame chopped off the end of the film.</p>

[adam_koch]

<p>Thanks for the responses. <br /> <br /> Joe: That is indeed part of the second to last frame that was chopped off. I always line up the film dead on the start mark of the insert. Some rolls have only small spacing problems like 1 frame skipped or just uneven spacing but some rolls like the one above are just a mess. Oddly enough whenever I have shot with ilford film the spacing seems to be less of a problem, that might just be a coincidence though.<br /> <br /> I will check all those parts you indicated and I'll order another insert, doesn't hurt to have a backup anyway.</p>

[adam_koch]

<p>I know this is a dead thread but I have been on haitus from my mamiya for a while, I bent the leaf springs on the back out a bit and I no longer have the skipping frames or the dead space on the roll. <br /> <br /> Thanks fellas, Adam.</p>

[Fototor]

<p>Hmm, one of my three 120 backs for my 645 Pro behaves in exactly the same way as yours did. I will give your remedy a try.</p>