Canon LTM QL17 GIII Beamsplitter replacement

Canon M39 M39 screw mount bodies/lenses
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Laurencet

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Hi all
My apologies if this topic has been covered elsewhere, I've hunted around and not come across the information.

My QL17's rangefinder patch is invisible under normal light conditions. I've cleaned the viewfinder and checked the RF alignment but this has made little difference. My hope is that I may be able to replace the beamsplitter with a part from another Canonet, but I'm not sure which other models might have compatible parts. The 19, 25 and 28 look very similar externally but can anyone tell me if I could use these (or any others) as donor cameras?

many thanks

Laurence
 
Rather than trying to pinch one off another old camera (especially one otherwise working fine), and dealing with the fact the mirror is probably at least semi-faded by now, I've decided to buy some brand new beamsplitter glass for my Lynx. I see Edmund Scientific sells it: http://scientificsonline.com/product.asp?pn=3043359&bhcd2=1232780859 .

Well, I would buy from them, except they don't ship outside of the US. Any suggestions?
 
http://www.rangefinderforum.com/forums/showthread.php?t=90468

Pop the top and get access to the semi-silvered mirror, same as the GIII shown in the above thread.

I just looked at a parts camera- and the semi-silvered mirror is cemented in place on both sides. Much more than the GSN and Petri cameras that I have removed the beamsplitter from. I used a exacto knife to get these out, but this will not work on the Canonet. Too much glue, the beamsplitter will break. I have a lot of parts cameras.

There is a small screw on the side of the viewfinder near the front glass- remove it. Pop out the front glass. I pried the viewfinder apart at that point with expansion pliers, and the glass came out BUT chipped at the bottom. I saved it, it would still work. I am trying a second parts camera by putting some Lighter Fluid (Ronsonol) on the cement to see if it loosens up. Will report back later.
 
The Ronsonol Successfully loosened the Balsam. Took out the front glass, and used the expansion pliers to pry the frame apart toward the front of the beamsplitter. It snapped away from the glass nicely, leaving it intact. With the front section loose, it easily wiggled out in one piece.

Now- your "good" camera, you cannot break the frame out- but the old glass can come out in pieces. Be careful. Clean the balsam out with a knife. New one shold go it the slots.

Well, what do you know. I have a spare beamsplitter for a Canonet. Let me know your success, and if you need me to send this one to you. If it works, please post the procedure on the "Mad Gearhead Scientist" forum.
 
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Hi Brian
I've just got back from a few days away - I'm not sure what sort of glue/cement I should use to replace the balsam, perhaps I don't need any...?

Thanks for taking the time to look into this, its much appreciated. I'll follow your advice and post back on here once I'm done.
 
When you see the slot for the beamsplitter you'll pretty know what to do. I used a little nail polish for the Lynx 14e. I suspect just a bit would do here as well. I was surprised at how much was used on the Canonet. More complex that I thought it would be.
 
Hi Brian
I've been doing this today and it was all going well until I came to drop the replacement beamsplitter from the 28 into the QL17. Its not a snug fit and there seems to be no way to fit it so that its held in place without moving, it moves about quite a bit. For example there seems to be no way to make sure its set perpendicular to the 'floor' of the rangefinder housing. This is obviously going to affect the focussing. Perhaps I should get it a square as possible and then rely on using the horizontal/vertical ajustment to get it right. Anyway I'm loosing the light now so I'll try again tomorrow and see how it goes.

I've just reviewed the photos I took before I began taking things apart and may be able to sort this now.....
 
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xwhatsit said:
Rather than trying to pinch one off another old camera (especially one otherwise working fine), and dealing with the fact the mirror is probably at least semi-faded by now, I've decided to buy some brand new beamsplitter glass for my Lynx. I see Edmund Scientific sells it: http://scientificsonline.com/product.asp?pn=3043359&bhcd2=1232780859 .

Well, I would buy from them, except they don't ship outside of the US. Any suggestions?
Click to expand...

I tried replacing the beamsplitter on one of my canonets with that exact same product. It didn't work for me.. I don't know if I was doing it wrong or what, but it was a complete failure.
 
With the glass being loose in place- the original is fixed in place with a lot of cement. Really cheesy way doing it. The Lynx was well fitted, with a noth on the glass to key it into place. Others I've worked use a frame. A home-brew fix, maybe try a thin strip of scotch tape or something like it to thicken the side up, hold it in place.
 
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