Compund shutter problems

[Laskadog]

I recently bought a Schneider Xenar 240mm f4,5 lens with a Compound shutter. I hadn't noticed or it just started doing this, but the B and T settings don't work consistently. I never forced the cocking mechanism while in B or T, but maybe someone before me has in the past, I don't know. I can get the B and T to work by shaking (more like spinning) the lens. I hear something move inside, then the B works until I move it to T or M and the T works, but only once. Anyone know just how broken this shutter is? I'm pretty handy (and adventurous), so I could take it apart if the repair is doable. Anyone have some experience in this matter that could shed some light?

Thanks,

Dave

[Luis-F-S]

I'd send it to SK Grimes or a qualified repair person. With old shutters, parts can be a problem and it probably just needs a CLA/Adjustment. Why chance it? L

[Pete Oakley]

Flutots are very good.
Pete

[Pierre 2]

Just open it up. The fact that you are handy (and adventurous) implies that your are qualified, provided you exercise care in disassembly and that you take pictures from various angles as you proceed.

At worst, you may have to order a part and at the very worst, you may have to send it in disassembled. Those things are made to be taken apart and a qualified shop won't have any problem in putting it back together (but neither will you, provided you conduct the whole operation on a very large piece of white linen, in order to effectively catch any screw or spring that you may drop). Pictures are really helpful to figure out how the springs should be reassembled. An other thing that will help built your confidence is proceeding to disassemble and reassemble many times, each time going a little deeper into the shutter.

Have fun - Its addictive :-)

[Laskadog]

Thanks for the advice. I will give it a try and like you say Pierre, I can always send the bits and pieces later. I've done much scarier stuff to my cars and cameras. I was just wondering if it was a common thing to happen and if it repairable without parts. Sometimes something just needs to be put back into place.

[Laskadog]

FIXED IT!!!! Ok, so for future records, here's the fix…

PROBLEM: Bulb (B) and Time (T) work intermittently or not at all. Shaking the lens makes them work again, but only briefly.

FIX: I removed the face of the lens by removing the shutter cocking lever (3 screws), the f-stop scale (2 screws), the shutter speed dial (1 screw). This gives you access to all 4 screws that hold the face plate. You can clearly see the mechanism and how it works. The problem is that the B & T system works when a long arm with a notch in it engages the shutter. This arm moves out of the way during M but was not moving back in after and therefore was not catching the shutter (see the picture with the red circle). The fix was actually pretty simple. A bit of oil between the plates and voilà!. I did remove the shutter button (or lever) to get better access, but this is super easy. Just be careful because there's a very tiny spring that recoils the lever. It stays in place, but don't bend or lose it. The hardest part was getting all those tiny screws back in. It takes a very good and thin screw driver.

Having seen the innards and how they work, I see now why moving the lens made the arm spring back into place. A temporary fix MAY also be to pull down the shutter button and let it go sharply making it spring back up. That also seemed to make the arm go back into place, but this would be temporary.

Hope this helps.

Cheers,



Dave

[Bob Salomon]

FIXED IT!!!! Ok, so for future records, here's the fix…

PROBLEM: Bulb (B) and Time (T) work intermittently or not at all. Shaking the lens makes them work again, but only briefly.

FIX: I removed the face of the lens by removing the shutter cocking lever (3 screws), the f-stop scale (2 screws), the shutter speed dial (1 screw). This gives you access to all 4 screws that hold the face plate. You can clearly see the mechanism and how it works. The problem is that the B & T system works when a long arm with a notch in it engages the shutter. This arm moves out of the way during M but was not moving back in after and therefore was not catching the shutter (see the picture with the red circle). The fix was actually pretty simple. A bit of oil between the plates and voilà!. I did remove the shutter button (or lever) to get better access, but this is super easy. Just be careful because there's a very tiny spring that recoils the lever. It stays in place, but don't bend or lose it. The hardest part was getting all those tiny screws back in. It takes a very good and thin screw driver.

Having seen the innards and how they work, I see now why moving the lens made the arm spring back into place. A temporary fix MAY also be to pull down the shutter button and let it go sharply making it spring back up. That also seemed to make the arm go back into place, but this would be temporary.

Hope this helps.

Cheers,



Dave

Very good! But you never removed the face of the lens. You removed the front plate of your shutter. That is a huge difference!

[Laskadog]

Oops, yes Bob thanks for clearing that up. I'm new to LF and not used to shutters and lenses being 2 separate parts

[LabRat]

DISCLAIMER; I'm a tech, and I discourage people from attempting mechanical camera/shutter repairs if they don't know EXACTLY what they are doing with them (as I have seen WAY too many more problems from the "repair" turning up)... If in doubt, send it out... Especially if one is smart and talented, it will only make one sadder if things don't go right... (Would you fix your own mechanical watch or automatic transmission!?!!!)
Most units can be tricky, and have parts that are very delicate, and springs fine as a human hair... And all makes are different, and have different needs... And parts not available anymore...

But having said all that, this is a common problem with this shutter... Those 2 arms that sit on top of each other are made from old aluminium... The material develops a very slightly tacky oxide coating/pitting/sometimes corrosion on the mating surfaces over time, and requires them to be carefully cleaned/polished so there is no resistance as they sit on each other... Oiling them will eventually gum them up (These shutters run mostly dry)...

But since you got this far, cleaning the parts with some wipe-on solvent (sometimes removal), and polishing the mating surfaces with a very small amount of graphite on an applicator (but don't rub too hard or you can warp the parts)... Then, leaving a tiny amount of the graphite between the arms to be used as a micro "spacer" between them... (But don't just shoot a lot of graphite into a shutter, as it is a microabrasive, and conductive, where it can short out flash contacts...)

Good luck with this...

Steve K

[Pierre 2]

Steve,

Thanks for the graphite hint.

As for the comparisons, hum... Just about any mechanical watch is way more delicate (did not say complex) than this shutter and if I could hold my 100$ transmission in the palms of my two hands and open it up with just two small screwdrivers for only tools, you bet I would fix it myself. However, there is another potential source of mishaps that has not been discussed : Mistakes happen and springs improperly unloaded single handed (as opposed to being restrained by the other hand) can and will often fly off quite fast - safety glasses to be considered useful for such a spring could effectively be found in an eye instead of bouncing of a wall prior to landing on the very wide piece of white linen.

Still, you are absolutely right in that it is possible for the unskilled and/or clueless to damage a part through a careless or mindless reassembly trial, let alone loose a number of parts.