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Jan Dvorak
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 24, 2004 - 10:28 am: | 
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Hello,
I am trying to revive an old Yashica Minister rangefinder (very similar to the Lynx line). The focus on the camera is completely frozen, I cannot move it from the infinity mark. There are no signs of impact damage or improper disassembly. I suspected dried focusing helicoid lubricant and soaked it in lighter fluid, hoping that it will penetrate and loosen the threads, to no avail.
I have the lens/shutter assembly out of the camera, the focusing scale ring removed from the helicoid and still cannot see a way to get the helicoid moving.
Any ideas anybody?
Thanks,
Jan |
Dan Mitchell
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 24, 2004 - 01:35 pm: |
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Is there possibly some sand or other "stuff" in the threads? I've had some cameras where a rangefinder mirror came loose, fell down into the helicoid and then got ground up. It was almost impossible to unscrew the helicoid to fix it. |
Jan Dvorak
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 24, 2004 - 02:07 pm: |
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Hello Dan,
The RF mirror was loose inside the top housing (now fixed), but so it was on another Minister which works perfectly. I think the glue that Yashica used to affix these mirrors was not very good and a lot of them simply worked themselves loose.
Nothing else is in the threads, that I can see. There is no evidence of sand, or other foreign material. If the camera was dropped, it would have happened in the eveready case, I don't believe that would have caused the helicoid to lock up.
Any other hints?
Many thanks,
Jan |
Scott
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 24, 2004 - 06:08 pm: |
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Try a little heat.
What I would do, if you do have the shutter assembly removed, and have removed the lens elements, is warm it up a little. This has worked for me when fixing 1950s cameras with stuck focus threads. You don't really have to make it hot, but if you can warm the whole thing up a bit, the hardened grease will usually soften up enough to allow you to unscrew the parts just using your hands. If just warmth doesn't do it, try it again a littler hotter.
I put the stuck pieces on top of an upside down pie pan in a large, covered wok over a low flame for a couple of minutes, then grab the piece with a dish towel and unscrew the parts while it's still warm. |
Howard
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 25, 2004 - 01:31 am: |
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Hi Jan, for what its worth I own several old Yashica's and I have never come across one with hardened lubricant. Most old Yashica's seem to focus smoothly regardless of whatever other problems they may have. I feel something may have fallen into the thread or perhaps it has corroded.
It's just a thought. Good luck! |
Jan Dvorak
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 25, 2004 - 11:39 am: |
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Thanks everybody!
This also is one of many Yashica rangefinders that I either own or have come across - the first one with a frozen helicoid. I will try the heat. I think if anything fell into helicoid threads there would at least be some movement, but I have none at all; literally frozen solid. Everything else works fine and the camera is in close to mint (as much as I dislike that word) condition - it would be a pity if I could not fix the focus...
Any other ideas are still appretiated, wish me luck!
Jan |
Jan Dvorak
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 25, 2004 - 10:48 pm: |
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SUCCESS!
I am happy to report that the operation was successful and patient is on the way to recovery. It was the heat that did the trick - I let the camera sit within 4 inches of a 60w table lamp (with the selenium meter window covered, just in case) and after about 1 hour of basking in the heat the helicoid responded to my efforts. At first the movement required a lot of force, after 5 minutes of soaking the helicoid threads with lighter fluid and letting it penetrate into the grooves, movement became a lot easier. Probably a little more tinkering and adding a proper helicoid lubricant will finalize the repair. Next, the rangefinder mirror will be re-glued, rangefinder re-calibrated and all should be well again.
Thanks for the hints,
Jan |
Howard
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 25, 2004 - 11:24 pm: |
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Well done. I have found that a product here in Australia "Shellite" which is probably sold worldwide dissolves the old grease really quickly and completely. I had tried a variety of things on an old Petri thread with little success, but the "Shellite" did the trick in a couple of minutes. I used synthetic bicycle grease afterwards and it worked really well. |
