Olympus Vanox AHMT interpupillary mechanism

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eKretz2
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Joined: Sat Jul 31, 2021 9:07 am

Olympus Vanox AHMT interpupillary mechanism

#1 Post by eKretz2 » Mon Aug 02, 2021 12:53 am

I tore apart my Vanox for a good deep cleaning and relubrication and found that there's a feature in the interpupillary mechanism that i hadn't been aware of until now. And it's broken! Any Vanox guys that are familiar with these scopes know why this is even present? As the interpupillary distance is changed, this mechanism would apparently move the eyepieces toward or away from the user of the microscope. They are on what look like 45° ramps, so that the eyepieces would move in or out the same distance that they move from center as the interpupillary distance is changed. The scope seemed to work just fine, although the pins that rode on the ramps were broken off and lying loose. I'm debating if I need to repair this or if it doesn't do anything useful.
Last edited by eKretz2 on Mon Aug 02, 2021 2:14 am, edited 1 time in total.

deBult
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Re: Olympus Vanox AHMT interpupillary mechanism

#2 Post by deBult » Mon Aug 02, 2021 1:02 am

Alan Woods website has loads of old Olympus repair guides (mainly BH2): the mechanism may be similar to the BH2 head?

http://alanwood.net/olympus/downloads.html#vanox

eKretz2
Posts: 62
Joined: Sat Jul 31, 2021 9:07 am

Re: Olympus Vanox AHMT interpupillary mechanism

#3 Post by eKretz2 » Mon Aug 02, 2021 1:14 am

Good idea. I'll hit up some of those and see what I can find. There's nothing in the available Vanox repair manual, didn't think to look at the BH stuff. Thanks.

Scarodactyl
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Re: Olympus Vanox AHMT interpupillary mechanism

#4 Post by Scarodactyl » Mon Aug 02, 2021 1:15 am

Yeah, the idea would be to avoid the focus changing as the oculars move (since moving horizontally changes the path length). Not a big deal if you're the only user and don't need to changge it, but probably worth fixing if it's easy.

eKretz2
Posts: 62
Joined: Sat Jul 31, 2021 9:07 am

Re: Olympus Vanox AHMT interpupillary mechanism

#5 Post by eKretz2 » Mon Aug 02, 2021 2:13 am

Found a brochure with a blurb about the mechanism. It does maintain focus for changing interpupillary distances, so that a camera in a trinocular port maintains parfocality with the eyepieces even for different users. While it is within my ability to fix, I think I will set it in one position and leave it alone. It would require machining some replacement parts since they're probably not available anywhere, which is not a problem; but additionally, I don't think I can get everything apart to replace the broken pieces without disturbing prism/mirror locations, which I definitely don't want to do.

carlh6902
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Re: Olympus Vanox AHMT interpupillary mechanism

#6 Post by carlh6902 » Mon Aug 02, 2021 3:05 am

That mechanism is the automatic tube length compensation for the Jetzsch style heads. It is absolutely necessary when using high performance objectives.

The bh2 mechanusm is this PDF is similar:

https://drive.google.com/file/d/1oWyF3o ... p=drivesdk


Carl
--- If you're in the Kansas City area and you need help with an Olympus BH-2 scope, PM me. I love to work on these things ---

eKretz2
Posts: 62
Joined: Sat Jul 31, 2021 9:07 am

Re: Olympus Vanox AHMT interpupillary mechanism

#7 Post by eKretz2 » Mon Aug 02, 2021 4:39 am

Carl, excellent write-up, thanks. You did a great job on that! That head is mostly similar to the Vanox, but not quite the same. For one, the Vanox doesn't appear to have the helicoid threads, nor any diopter adjustment. The mechanism for tube length compensation appears to be identical though. The parts you have labelled as follower keys are both broken on my scope. It would seem that the grease solidified/got sticky and someone brute-forced the interpupillary adjustment, snapping them off. The mechanism has been sloppy since I got it, this is the first time I have investigated. One of the little brass pins for the pivot lever mechanism came loose too, but I was able to put it back in place and re-peen it so it was nice and tight again. Perhaps I will take a crack at fixing it after all. I don't suppose you know of anywhere to get those follower keys? If I have to make them I will, but if they're available...

eKretz2
Posts: 62
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Re: Olympus Vanox AHMT interpupillary mechanism

#8 Post by eKretz2 » Mon Aug 09, 2021 10:20 pm

Well, I picked up a BH2 parts scope with a bino head that had the same mechanism as the Vanox pretty cheap thinking I'd find the parts I need. Nope, they're different. Pins are just enough shorter that they won't work. Just FYI in case anyone else with a Vanox runs into this.

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