Compur shutter models

dario · May 27, 2018

Hi folks

I've just bought a 300mm f9 Rodenstock Apo Ronar lens. The shutter is a compur 1, but unlike other shutters I have, this one has no self timer, no MVX switch, and no "B" setting. The "T" setting is adjacent to the 1/500 setting (usually it's by the 1 second setting). Its serial number is 4 079 356. On the back it is stamped in red with "B48".

I'd like to lift the face plate off, because it has a small problem to do with the T setting, which I think I could fix. But I can't find any manual, you tube video, or relevant instructions.

Can anyone help, please?

shutterfinger · May 27, 2018

Post a picture of the shutter. Compur, Compur Rapid, Synchro-Compur. There are a 3 or 4 sizes of each with several variants of the base shutter for various camera or lens usage.

dario · May 27, 2018

Hi
Here are some pix.
I should have added that there's a lever for cocking the shutter (of course) for the various shutter speeds, but for the "T" setting there's a second lever that, on its first operation, opens the shutter and cocks a spring that on operating the lever a second time snaps the shutter closed. There's no socket for a cable release, although there's a square hole in the case where this would go.

shutterfinger · May 27, 2018

I'm not familiar with that new of a shutter other than how to open/remove the cover. On the notched ring in the front center there should be a screw in one of the slots. Mark the slot, remove the screw then count the turns it takes to remove the ring. Now lift straight up on the cover noting its orientation. Some covers are flat on the bottom side while others are machined out in places to allow various levers inside to operate. Incorrect orientation or over tightening on reassembly will prevent the shutter from running correctly. Copal shutters are built similar.

dario · May 28, 2018

Thanks shutterfinger. That's a great help. I've removed the face plate and identified the problem. The lever that opens the shutter when set to 'T" is not engaging properly. It seems to be just a matter of a tiny bit of play, perhaps due to wear. Not sure if I have the skills to fix it.

shutterfinger · May 28, 2018

Once again, POST A PICTURE!

dario · May 31, 2018

Sorry, it's all back together now and seemingly fixed. I don't dare take it apart again. I'm not sure if I should admit how I fixed it. When the shutter speed ring is rotated to the T position , it engages with a small pin. However, the pin was not being pushed across quite far enough. It seemed only a matter of a few tenths of a millimetre. I couldn't see any means of adjustment and was too scared to disassemble the mechanism further. (I once thought I could fix a shutter and in the end had to take the bits to a technician!) So, I put a very tiny dab of Arladite (as much as I could get on the point of a needle) on the shutter ring where it engages with the pin and baked it in a warm over, so the Araldite spread out into a thin film. I then reassembled the shutter and found that the film of Araldite provided just enough further movement of the pin. Fingers crossed! Thanks again for your help.

shutterfinger · May 31, 2018

OK, you got it working. Other techniques is to swag the ring where it contacts the pin by placing the ring on a solid surface then use a small punch and hammer 1/32 behind the contact point or bend the pin toward the ring a degree or so.

dario · May 31, 2018

Thanks Shutterfinger. I don't think I'd have tried the swaging idea, but I'll keep it in mind. It's always interesting to learn a new technique.

Do you have any idea why the lens would not have had a cable release socket? There's a square hole in the case where a socket would have been mounted. Maybe it was intended for use on a camera that had a cable release socket mounted on the lens board?

shutterfinger · May 31, 2018

Its possible someone removed it or the shutter came off a camera that had external trip mechanism. The aperture lever on the rear looks like a gear has been remove also suggesting remote or electronic aperture operation such as on a copy camera.

dario · May 31, 2018

That's interesting. The lens is a 300 mm f9 Apo Ronar, which I think may haev been intended for copying work.

shutterfinger · May 31, 2018

Copy/process lens/shutter. Optimized for1:1, good performer at infinity also.

Compur shutter models

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