A12 Magazine - Crank Mounting problem

logan.egbert · Oct 30, 2016

I just took apart a cranky A12 back to lube and grease it and everything is running super smoothly. The only issue is that the crank mount won't 'catch' on the gear inside the back to allow me to wind the back.

I think the issue is with the little spring pictured here. There is no tension in the little arm because the spring seems to be in the wrong position. But I don't have any empty magazines to double check against.

Has anyone ever had this issue? Any solutions?

Thanks!

logan.egbert · Oct 30, 2016

Here's that arm and spring for reference

logan.egbert · Oct 31, 2016

APUGuser19 said:
Open it back up and get it right. You likely have a good first effort, but there's obviously a sponge left in the patient.

It's still open. I can't figure out how this spring is meant to be positioned. It's maddening to be so close but unable to get it wrapped up.

chrisaisenbrey · Oct 31, 2016

I guess the spring should press the little arm against to other straight spring.
The following video shows the “Crank mounting“ at around 3:50:

Sirius Glass · Oct 31, 2016

Wow, that repairman is really fast!

John Koehrer · Oct 31, 2016

Paid piecework!

Leigh B · Oct 31, 2016

That is perhaps the worst "instructional" video I've ever watched.

- Leigh

M. Axel Wikstrom · Oct 31, 2016

I liked the video. Pretty easy to follow how to get things loosened up and working again - have two magazines in need of that. Don't know if I'd want to go any further than that, aside from changing light trap seals anyway.

logan.egbert · Nov 1, 2016

chrisaisenbrey said:
I guess the spring should press the little arm against to other straight spring.
The following video shows the “Crank mounting“ at around 3:50:

This is the video, combined with Hasselblad's repair documentation that I used to piece together how to service my magazine.

The problem with my back is that the spring has come undone and I don't know where to set the second part to get it to line up like you say at 3:50 in the video.

logan.egbert · Nov 1, 2016

M. Axel Wikstrom said:
I liked the video. Pretty easy to follow how to get things loosened up and working again - have two magazines in need of that. Don't know if I'd want to go any further than that, aside from changing light trap seals anyway.

Once you have a back open and can poke and prod it, you start to see just how things go together. That combined with Hasselblad's documentation can get you as far as disassembling it to a point where all the major spots can be lubed and the gears can be greased. Once you do that, the thing is smoother than a baby's behind!

M. Axel Wikstrom · Nov 3, 2016

I just took two of them apart to clean and lubricate them.

The base of the crank, inside the cover, has a pawl that engages the spline drive of the clockwork. If that pawl gets pushed around backwards and underneath the circular plate inside the bottom of the crank, it won't engage the spline. Be sure that the pawl is in the correct position, and turn the crank backwards (counter-clockwise) as you push the cover back on. Turning the crank backwards keeps the pawl in the correct position as the cover is pushed on.

It works like a ratchet - clicks with not much resistance when turned backward, and engages when turned clockwise to turn the mechanism.

logan.egbert · Nov 6, 2016

M. Axel Wikstrom said:
I just took two of them apart to clean and lubricate them.

The base of the crank, inside the cover, has a pawl that engages the spline drive of the clockwork. If that pawl gets pushed around backwards and underneath the circular plate inside the bottom of the crank, it won't engage the spline. Be sure that the pawl is in the correct position, and turn the crank backwards (counter-clockwise) as you push the cover back on. Turning the crank backwards keeps the pawl in the correct position as the cover is pushed on.

It works like a ratchet - clicks with not much resistance when turned backward, and engages when turned clockwise to turn the mechanism.

Do you happen to have a picture of how the spring that control's the pawl's movement should be arranged relative to the pawl? As you can see above, mine is not how it's supposed to be.

M. Axel Wikstrom · Nov 6, 2016

logan.egbert said:
Do you happen to have a picture of how the spring that control's the pawl's movement should be arranged relative to the pawl? As you can see above, mine is not how it's supposed to be.

I did not, but looking at your photo, you may want to try hooking that loose end of the spring over the top of the pawl. I don't know if that will work, but it's worth a try. There should be just a just a little bit of spring pressure on the pawl to keep it engaged with the spline.

logan.egbert · Nov 11, 2016

For everyone's reference, I fixed my back.

The top spring has to be fitted in a groove on the back (flat) side of the pawl. You have to carefully slip it in there and then get the pawl to catch on the main gear and then it's good to go.

M. Axel Wikstrom · Nov 11, 2016

logan.egbert said:
For everyone's reference, I fixed my back.

The top spring has to be fitted in a groove on the back (flat) side of the pawl. You have to carefully slip it in there and then get the pawl to catch on the main gear and then it's good to go.

Excellent

A12 Magazine - Crank Mounting problem

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