Compur SV shutter dismantle

Rekusu · Sep 14, 2024

What ho one and all,

Attempting to repair a Compur SV shutter from a Yashica Campus camera. Have removed the lens and opened the ;shutter mechanisum. The slow speed appears to works, as does the timing escapment, but the actual shutter blades are not moving at all. Wnat to get deeper into the shutter as the ring that opens / closes the blades appears to be locked.

On the back, looking at the aperture ring, there are two small holes that are the end of two screws. If these are released, I assume the rings will come off, allowing access to the shutter blades. By rotating the ring, I can find a screw on the screw access point on the front and when I released this screw, indeed, the aperture ring was loose. But there does not appear to be any access to the other screw. Any advice would be greatly appreciated.

Red arrow show the ends of the screws on the aperture rings to which I have access but the green arrow is the end of the other screw that seems to have no access..

On the inside, the red arrow shows the access hole with one screw lined up and the red X is the approximate location of the other screw but with no obvious access.

Thanks and toodle pip

OAPOli · Sep 14, 2024

It's a Copal SV no?

I think you need to toggle the flask sync selector, it'll reveal the screws. There are lots of tutorials online for similar shutters.

You'll also need to remove the pin in the cocking actuator. That requires a custom tool.

Rekusu · Sep 14, 2024

Thanks for your reply. Certainly from the back, by moving the flash selector, three screws do become visible but they are not at 120 degrees so not sure. It may be that they hold two parts together but certainly will not allow the rear plate to be removed.

Regarding the 'special tool' to remove the cocking actuator, I guess that is to remove the small T. It can only be a press fit, so perhaps a bit of DIY pressure will do the job. Or a bit of heat with a soldering iron to expand the shaft?

My understanding with further investigation is that once the cocking actuator and the screw in the first photo at the 3 o'clock position are removed, then the plate can be rotate a further 180 degrees to get access to the screw from the same position as is visible in the second photo.

It is all a steep learning curve!!!

Rekusu · Sep 14, 2024

Thanks. I have a sledge hammer in the back of the garage!!! I think the bigger issue is my 'not so good' eyesight. After extensive close investigation and shining bright lights, I can see a micro C clip on the cocking actuator shaft. That will be easy to loose!

The good thing is that I do like a challenge and am enjoying this. But, it is a friend's camera and although he has said he is not worried, as my first proper repair, I would like to fix it for him.

All good fun.

OAPOli · Sep 14, 2024

You can grind a "U" notch in one jaw of a pair of pliers to deal with the pin.

Watch out for the blades once you've split the shutter. They usually have spacers. First 4 go under the blades, the last goes over.

Rekusu · Sep 14, 2024

Thank you for that information; very useful when get inside the shutter. As you suggested in a previous reply, there are plenty of videos on similar shutters, but from what I have read, each manufacturer made some of there own 'adjustment.' Hence, I have not found anything on how to actually get to the blades on an SV shutter from Yashica.

One site shows undoing four screws on the back; mine does not have those screws so slightly stymied. As a newcomer to this hobby, I'm slightly concerned about removing some screws, finding the problem and then, not having any idea on how to reassemble because I have done something in the wrong order. I know, notes and photos.

In this case, i don't think the blades are stuck as there is no evidence of grease, but I do think the ring that the blades are attached to is stuck.

Will keep the thread updated when I get around to the next stage.

Rekusu · Sep 18, 2024

have not managed to remove the cocking actuator pin yet, but using my verniers to measure it, I do believe it is tapered.

Have just put a drop of thinners on it and waiting for the soldering iron to heat. Hopefully, a bit of heat will expand the shaft sufficiently to release the pin. then I will drop it and loose it forever!

Rekusu · Sep 19, 2024

Do not know how that pin on the cocking arm is held in place. Seems to be slightly tapered, but to date, neither solvent, gentle heat, gentle taping nor direct pressure with a pair of pliers is moving it. Concerned that it will bend or snap before it moves.
As and FYI, it is the pin circled in red. The cocking shaft is held in place by a C clip and washer, but cannot be removed unless the pin is removed first.

The reason I need to remove it is that the ring onto which the shutter blades are attached and which rotates to cause the shutter to open, is totally locked. it will not move whatsoever, even with the timing and self timing unit removed. Something is obviously preventing it moving!!!

Any thoughts gratefully taken on board.

OAPOli · Sep 19, 2024

My suggestion is to make a custom tool as described above, and making sure you are pushing on the small end of the pin, which is tapered.

Rekusu · Sep 19, 2024

Will give it a try; just have to find a very small pliers.

Rekusu · Sep 20, 2024

Thanks for the photos. Have been trying to tap it out with a block of wood and albeit, not an upholstery hammer but a small model-making hammer. It has a very small head but certainly sufficient oomph to dislodge the pin. All I have managed is to bur the end of the pin. And yes, I am tapping it in the correct direction!
Will look for a pair of pliers to file a notch and I have a small precision modelling making drill that I may be able to clamp for turning.

Rekusu · Sep 21, 2024

Gentlemen,
I am really getting my knickers in a twist over this one.

I have found that there are in fact four screw around the outer edge that when release, allow the entire shutter and aperture blade assembly to slide out of the main body. All very easy with a big BUT.....!

That little rod for the shutter cocking needs to be removed and it will not budge. I made a tool and all I am managing to do is score the end of the rod. I have heated it directly with a micro flame hoping to expand the shaft sufficiently to tap the rod out, and nothing. I am concerned about bending or snapping the rod but that seems to be the only way to separate everything.

Having release the four perimeter screw, and twiddled with the inner part, the shutter blades and shims have now fallen out. I have dismantled everything and now reassembled (without the shutter blades, timing and self timer) and and surprisingly, the shutter actuating ring now rotates and when cocked by hand, everything appears to be working.

So now I have to get that rod out to reassemble, but how?

Any additional suggestions great appreciated.

Thanks and toodle pip

PS Apart from being a great learning experience, I feel I am really close to getting it working again. Not prepared to give up just yet!

OAPOli · Sep 21, 2024

Can you show a pic of your tool?

Dan Daniel · Sep 21, 2024

Seems a pair of pliers like this with a notch in one tip for the pin. Put notch on fat side and clamp away?? THis will keep the pressure equal on the large vertical part, lessening the chance of snapping it off. Not certain what you are using.

Rekusu · Sep 30, 2024

Time for an up-date. I did grind a slot into a needle nose pliers but that also proved to be no good. Decided that if I gently hammer the pin, it should come out and if it breaks, I will drill a clearance hole and replace with a pin of the same diameter.

Well, it did finally come out so drilling not required. In separating the shutter from the body, I found that the two screws arrowed in my first post, where accessible as they hold aperture blades in place. Cleaned the shutter and aperture blades; challenging to reassemble and get all the pins correctly installed.

Installed the timer and self timer and the release mechanism and it all works as it should. Then dropped the little cocking pin and cannot find it, so did reduce a pin to the necessary diameter, wedged it in place. In fact, it does not need to be a tight fit (just snug) as the cocking shaft in the camera body, when all fitted together, encloses the pin and prevents it from falling out.

Camera reassembled, leatherette stuck with a smear of PVA and all working like ti just came from the factory.

A challenging and interesting learning experience, now hungry for another camera; I have three SLR from eBay and a Zorki so plenty to keep me amused.

Very grateful for the advice and assistance.

Compur SV shutter dismantle

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