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Evisc
Tinkerer
Username: Evisc
Post Number: 17
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 28, 2008 - 11:29 am: | 
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So I'm trying to disassemble the taking lens on a Yashica Mat-124G TRL to check for fungus (hopefully it's just oil or grease).
Anyway, after removing the front cover I try unscrewing the front element of the taking lens (just as I did on my rollei), but it's stuck.
Here goes; does the taking lens unscrew, or is there some other way?
If it does unscrew, how would you go about loosening the lens? |
Lucas
Tinkerer
Username: Lucas
Post Number: 57
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 28, 2008 - 01:39 pm: |
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On a 12 I used to have I had better luck unscrewing the back lense element and cleaned from the back with the shutter on B. I used a hardwood dowel to unscrew the ring that holds the element. |
Dgillette4
Tinkerer
Username: Dgillette4
Post Number: 148
Registered: 04-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 28, 2008 - 05:09 pm: |
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I have used a rubberband on the outer lens housing to unscrew it, That usually worked, It then came off as a complete unit, and while it's open you might clean the apeature, The viewing lense is different, the whole front comes off by loosening a set screw and un screwing the lense, It then has to be set for correct focus if you do. This is a great way to make sure the film plane and the viewfinder agree. Don |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 491
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 28, 2008 - 07:12 pm: |
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It unscrews.
Try wearing a pair of rubber dish-washing gloves... they give you one heck of a grip, and they're less clumsy than trying to juggle a piece of rubber sheeting. |
Evisc
Tinkerer
Username: Evisc
Post Number: 21
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 01, 2008 - 01:43 pm: |
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Thanks for the advise! The lens remain stuck though... I'm afraid that if I try any harder it will break! I'll keep trying...
Any more ideas? |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 498
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 01, 2008 - 04:49 pm: |
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It's a little extreme, but I've had to do this on a number of Mamiya TLR lenses so I know it works: Get a small worm-gear type radiator hose clamp, big enough to fit the lens, and cut a piece of rubber sheet, about 1/16" thick, sized to wrap around the lens between it and the clamp to give a grip and prevent scratching. Tighten the clamp up well over the rubber so that it has a good grip.
Now, get a small hammer, and strike the protruding screw on the clamp in the direction that will start the lens turning counter clockwise. It's basically an impact wrench for a lens cell. You might want to mark the lens rim and the shutter with a felt pen first for reference ..... once you see any movement of the cell, it should be loose enough that you can remove the clamp or at least put down the hammer and unscrew it with your hands.
(....and, no, i've never broken a lens doing this...) |
Dgillette4
Tinkerer
Username: Dgillette4
Post Number: 151
Registered: 04-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 01, 2008 - 08:14 pm: |
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I think Rick is on the right track but I might use a channel locking pliers carefully on the hose clamp. Also a slight amount of acetone near the point the lens meets the flange first might help. Don |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 499
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 01, 2008 - 08:26 pm: |
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the pliers can offer good leverage but be very careful not to clamp down with them. |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 94
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 02, 2008 - 09:49 am: |
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The taking lens cells come off by unscrewing. You jhave to take off the front cover which reveals the shutter. I use a pair of large hemostats with tubing over the tangs to get a good non-maring purchase on the lens. The original lenses were tacking on with some varnish so maybe wicking a bit in the threads may loosen it up a bit. I've also used heat to loosen stuborn lenses by leaving em in the sun on a window sill for a few hours, then try unscrewing em.
To get the rear cell off, remove the entire shutter mount by taking out the 4 corner screws otherwise there isn't enough room inside the camera to get a hold of the rear cell. When taking the entire mounting plate off, just be aware there are shims under the screws, so carefully watch for them and be sure to place the same shims back where they came from when reinstalling or the edge focusing will be out.
The viewing lens is held in my a set screw taht is accessable from under the shutter mount. If you remove this you'll have to realign the focusing of the view screen to the film plane. |
Dgillette4
Tinkerer
Username: Dgillette4
Post Number: 152
Registered: 04-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 02, 2008 - 10:03 am: |
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One other thing, Can you see haze in the front or rear glass? If it's the front it won't be so big of a job.Hopefully you won't have to remove the deck with shims. Otherwise you will have to check for shims as mentioned. Don |
Evisc
Tinkerer
Username: Evisc
Post Number: 22
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 05, 2008 - 03:33 am: |
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Thank you all for good advice!
The haze is on the rear element. I tried to remove the mounting plate, but some previous owner seems to have poured lock tight on all the screws! Guess he didn't want the camera to be opened... Tried heating the screws, but haven't the right tools... |
