Compur Rebuild

[jayzedkay]

The shutter started acting up on my ZI Donata, after semi-dismantling it appeared to be the cocking-ring binding around the main body.
Seeing that it was part dismantled i put the lot into a small tub full of IPA, not the hoppy beer, but 90 odd % iso-alcohol.
That tub went into the ultrasonic cleaner full of generic cleaner. Smells like windolene, but 100 times more expensive?

Anyway, it all came out clean with minor debris and discolouring within the IPA.
Dried off and lubed up, i bought a watch oiling kit with small amounts of moebius oils & grease.

test-assembled and operated it now works fine; all speeds, T & B. Even the self timer is good.
it worked great before, so no real improvement other than back to where it was and no binding.

But, i have this wire-spring, that i don't think it sitting correctly? I think it may even have become distorted.
It's somewhat loose and sloppy on the pin it's wrapped around?

It doesn't seem to do anything now, i thought it was acted upon when the speed-ring was set to 200?
i have an image of the same spring on this site, but its different, so not sure?

Camera Collecting and Restoration

A photo/description of how it should be would be great?
TIA.

 

[OAPOli]

That's the booster spring for the fastest speed setting. You haven't specified which shutter this is but on modern Compurs that spring would be a bit straighter. It's normal for it to be loose on the post. How is the fastest speed?

 

[Tel]

Comparing your photo to the one in the link, it looks like you've got the orientation wrong--it seems like it should be rotated counter-clockwise about a quarter turn.

 

[OAPOli]

@Tel the spring is loose on the mount. It'll get properly positioned by the speed setting cam plate.

 

[BrianShaw]

See page 21, figure 103

https://www.suaudeau.eu/memo/manuels_rep/obturateurs/compur_rapid_shutter_repair%282%29.pdf

 

[retina_restoration]

That's the high speed tensioner spring. It doesn't engage except when selecting the fastest shutter speed, at which point there is a cam on the speed selector ring that engages the C-shaped curved section, applying much more force to the shutter. You can see the behavior of the high speed spring only when you have the speed selector ring re-installed: rotate it to the highest speed and you will see how the cam surface on the ring contacts and loads that spring.
It does look like it's been distorted a bit — probably by someone repeatedly setting the speed ring to the highest setting AFTER the shutter is already cocked, which is why you see it in many shutter manuals NOT to attempt to set the high speed if the shutter is already cocked. This is the kind of damage that can (and often does) occur. Doesn't mean it won't still work, but it appears to have suffered some.

 

[jayzedkay]

Thanks for all the replies. I have it sorted now.
Tel was on the money, it appears to have 'rotated' out of alignment. Must have been when i replaced the cocking-ring.
I put it back in the correct position. now the cocking-ring-tab tensions it, when the speed-selector is at 200 and the speed-cam is against it.

i need to touch up the matt-black coating where the IPA has removed it a little.