Dismantling and cleaning a Leica trinocular head (501500)

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boffin
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Dismantling and cleaning a Leica trinocular head (501500)

#1 Post by boffin » Sun Mar 06, 2016 1:41 pm

I picked up a used Leica trinocular head (model 501500) which has a bit of fungus in the left tube. Does anyone here know if it possible to take apart the head and clean the optics?

I have tried looking online for a service manual - no luck there.

Thanks in advance!
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Charles
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Re: Dismantling and cleaning a Leica trinocular head (501500)

#2 Post by Charles » Sun Mar 06, 2016 3:47 pm

A picture of the whole head from different angles would be helpful.

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lorez
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Re: Dismantling and cleaning a Leica trinocular head (501500)

#3 Post by lorez » Sun Mar 06, 2016 7:33 pm

Since it appears that you have a pretty bad situation now it probably would not hurt anything to give it a go.

I don't know where the damage is, but when you see the prism surfaces you will be able to determine that.

It's been a couple of years since I've done one of these so I can't offer too many step-by-step details.

You will need a centering eyepiece and stage target to make the final alignment.

lorez

boffin
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Re: Dismantling and cleaning a Leica trinocular head (501500)

#4 Post by boffin » Mon Mar 07, 2016 1:12 am

Here are additional pictures of the head.

lorez, I may be able to get access to a centering eyepiece and stage target - a friend works with Olympus scopes but hasn't touched Leicas. How delicate is the task at hand?

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lorez
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Re: Dismantling and cleaning a Leica trinocular head (501500)

#5 Post by lorez » Mon Mar 07, 2016 1:29 am

How delicate is the task at hand?
It's pretty well constructed so that helps with everything. Getting it apart is a 2 on the 1 to 10 scale. Putting it back together is a 9, not because it is heavy lifting but because it must be exact.

If your friend understands the principles of the head he will know what is necessary.

lorez

Charles
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Re: Dismantling and cleaning a Leica trinocular head (501500)

#6 Post by Charles » Mon Mar 07, 2016 1:31 am

I have never worked on Leica heads but it seems like you should be able to remove the two screws circled in red to remove the side cover and get access to the prisms.
Head.jpg
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boffin
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Re: Dismantling and cleaning a Leica trinocular head (501500)

#7 Post by boffin » Mon Mar 07, 2016 1:44 am

Great minds think alike! The same idea occurred to me after taking the photos so here's the outcome:

The central prism looks OK.
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Some minor fungus perhaps starting?
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The right prisms are where the action is concentrated. Looks quite grim here...
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Left appears in good shape.
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Fungal growth on optics is pretty much a fact of life here in the tropics. Camera equipment has to be kept in a dehumidifying cabinet when not in use and it looks like I need to buy another just for the microscope! Thankfully, I have the original binocular head, which is clean and fungus free, to fall back on while I deal with this issue.

Is it worth taking a crack at dealing with this? Take it to the Leica service centre (will be expensive) or just use it till it is condemned and buy another? I saw the problem when viewing the head and took the risk given the asking price was US$300.

Charles
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Re: Dismantling and cleaning a Leica trinocular head (501500)

#8 Post by Charles » Mon Mar 07, 2016 1:57 am

Have you tried to clean the top of the prism as circled here on the dirty one?
Prism.jpg
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boffin
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Re: Dismantling and cleaning a Leica trinocular head (501500)

#9 Post by boffin » Mon Mar 07, 2016 10:07 am

Yes, no problems getting to that surface with lens tissue. Unfortunately, that is not the problem surface. The fungus is growing on the inner side of the prism and is reachable only if I can remove the glue holding it in place.

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