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Alan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 04:53 am: | 
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fixing up a battered old contaflex ii for a couple of weeks now and i'm slowly bringing it back to life. i've removed the shutter/lens assembly and cleaned both the shutter and aperture blades so they are extremely smooth and free-moving, and i've soaked the clockwork mechanism in naptha to free that up. however, on reassembly the shutter will only fire on alternate wind ons (unlike before when the shutter fired every time but the timings were all out)
can anyone point me at the right cog?
also, since assembly the clockwork mechanism is again running slow and seems unable to fire the shutter in self-timer mode. time to disassemble again...
Alan |
Alan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 07:06 am: |
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p.s. turns out that the shutter only seems to fire when the aperture is fully closed (f22). maybe an aperture tension issue? any help greatly appreciated. |
Jon Goodman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 08:15 am: |
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Hello, Alan. Three thoughts: One, when you clean the shutter, make completely sure it is going to work once it is dry. This may mean leaving it alone a day or two. If the action is not crisp every time on the slow speeds, clean it until it is. Check the self-timer, too. Two, be sure you clean the gear train well. If any of the gears are dirty, the "wheel" will hang at the very end---right as it smacks the release lever on the shutter. I think this comes from people leaving these cameras cocked for many years...the spring loses its punch, and any resistance takes too much out of the action. Three, be sure you are tensioning the aperture correctly. When you do this, first--open it to 2.8 to get the blades fully open. Then close it to 22. Then rotate the star wheel counterclockwise until the blades have closed fully (or to 22). Keep turning until at least 20 (but not more than 22) of the star wheel points have passed the lock screw opening. I use a couple of bamboo rods to do this...it isn't easy with the shutter mounted. Holding the star wheel in place, tighten the center screw and replace the lock screw. All should be working fine then. Good luck.
Jon |
Jon Goodman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 08:23 am: |
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PS...when all is finished, cock the camera, set the shutter speed for 1/500 and the aperture at 22. Remove the back, point the lens toward a light source and fire the shutter. If you don't see a quick and very tiny point of light, your camera isn't going to work correctly. Alternatively, you can set the aperture to 22 and the shutter to 1/1. If you see the aperture blades still closing (or at any aperture opening except 22) when the shutter opens, your camera is not going to work correctly. Incidentally, this is the first thing to check when you buy one of these. The aperture is the first part of this mechanism to get sticky. Once it does, the pictures will forever be overexposed...no matter what you try to do to compensate. I hear from dozens of folks a year who say "the shutter in my Contaflex seems ok, but it takes lousy pictures." In over 9 out of 10 cases, a sticky and out of synch aperture is the answer. The aperture and the shutter must work together in complete precision.
Jon |
Alan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 09:27 am: |
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hi jon. 1a) action of shutter and aperture are smooth as when activated via triggers at the rear of the shutter assembly. 1b) shutter mechanism was running clean and crisp at all speeds, but after assembly slow speeds have degraded - will clean again. 2) gear train was working before disassembly so i don't think it will be this, but i'll give them a clean and light lube just in case. 3) followed this procedure on reassembly (thanks to this forum) and turned 20 "clicks".
how should the various wheels within the camera body be aligned when replacing the shutter? perhaps i've misaligned one... the shutter was released on both body and shutter and the gap in the chrome aperture wheel was showing at approximately 11 o'clock thorught the slot in the brass wheel. i'll take a pic once i've got it undone again. thanks for your help Jon - time to get the solvents out again  |
Jon Goodman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 10:48 am: |
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Hi, Alan. The two wheels (that cock/activate the shutter and open/close the aperture) normally do not get out of whack unless they've been removed. The cocking/activating wheel ends its travel about 1.6mm from where the end of it would allow no further travel (you can see how this would happen if you look at the bottom of its arc of travel and watch for what would naturally stop it). It is unlikely this wheel is "off" if the shutter fires at all, however. Usually if this wheel is off by enough to make a difference, the shutter will not cock or fire correctly at all. The aperture wheel must simply be set so that the aperture controlling tab fits into the slot in that wheel...this is either better demonstrated with some images or in careful language while it is being done. One of those things like juggling. I can do it, but teaching it via the written word is devilish difficult.
If the gear train has any resistance, it will (a) cause the shutter not to fire or (b) cause the shutter to fire randomly, after a pause, intermittently or sometimes not at all. It can have more of an effect than one would think.
The slow speeds...in your case, I'm inclined to think the shutter had not completely dried.
Jon |
Alan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, July 06, 2005 - 05:08 am: |
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cheers Jon - had the whole shutter assembly (minus glass) soaking in naptha overnight - removed and allowed to dry this morning but same problem eventually reappeared (same thing has happened after the previous 6 or 7 flushes). tried a different approach and used some light oil with teflon to free up some of the works - immediately worked. i'm letting it sit to lose any solvents and then i'll try it again but it seems better. is there any danger in leaving it oiled? there's no sign of oil on the shutters, and everything seems to be running smoothly. |
Jon Goodman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, July 06, 2005 - 07:56 am: |
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Hi, Alan. As long as it is working smoothly when it is good and dry, I'd say you'd be ok to leave it like this. I've run across a few leaf shutters which for one reason or another needed some "help"...usually in the form of a wee bit of graphite powder. Over the long haul, oil is going to attract dust and slow things down, but let's see what happens when it dries thoroughly. If the problem persists, wash it well with naphtha again and we'll try another angle.
Jon |
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