AO Stereo Star Zoom 580 Help Needed

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mhfan
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Joined: Sun May 02, 2021 6:30 am

AO Stereo Star Zoom 580 Help Needed

#1 Post by mhfan » Sun May 02, 2021 7:41 am

I'm new to the forum and this is my first post.

I have an AO 580 zoom body and the left ocular is much darker than the right. The right seems to work properly at all the zoom settings.

To troubleshoot the issue I switched the eyepieces and the problem remained at the left. Also, I opened up the cover of the zoom body and I saw all the optical elements moving in synch on both left and right. I also tried to obstruct the light at the different optical elements in the zoom body while looking from the bottom and it seems that the problem is not there, it's in the left ocular. I looked at the attaching nut of the oculars from the inside, and they are tight, did not attempt to remove it, as I thought I'd make more damage.

I attached a picture - from the bottom. Here I turned it around so the left side from the top corresponds to the left side of the picture.

I have never repaired microscopes, so I'm very cautious, did not want to create more damage.
Any help is greatly appreciated.

Thanks,
Steven
Attachments
Dark-side-1.jpg
Dark-side-1.jpg (101.98 KiB) Viewed 2841 times

Scarodactyl
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Re: AO Stereo Star Zoom 580 Help Needed

#2 Post by Scarodactyl » Sun May 02, 2021 8:28 am

That's weird. Aside from the brightness is it working, with the two images aligned with one another?

mhfan
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Re: AO Stereo Star Zoom 580 Help Needed

#3 Post by mhfan » Sun May 02, 2021 10:24 am

When you look into the two sides, the left seems completely dark, no image seems to be coming from there, so I cannot comment on overlapping.

Also, just to mention, this body may have had a photo attachment on the right side. It's not there anymore, the right side photo door is closed by the proper part. Is there something on the left side, which needs to be removed when the photo attachment is removed?

apochronaut
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Re: AO Stereo Star Zoom 580 Help Needed

#4 Post by apochronaut » Sun May 02, 2021 2:46 pm

There is a polarizer on a bracket for each optical tube that is in there . You can see it when you remove the trinocular cover plate. Maybe a ptoblem with one of those?
However something looks odd between the two sides , like the lens elements are out of sync or one is missing on one side . The aperture size and or magnification seems different.

mhfan
Posts: 7
Joined: Sun May 02, 2021 6:30 am

Re: AO Stereo Star Zoom 580 Help Needed

#5 Post by mhfan » Mon May 03, 2021 7:12 am

Thanks for the reply.

I took out the side cover and attached a picture of the two polarizers on the bracket. They seem to be nice and clear.
Polarizer-1.jpg
Polarizer-1.jpg (142.77 KiB) Viewed 2766 times
Also, with the open side I put in a red post-it and while allowing light from the side I took a picture from the bottom. Please note that the body is turned around 180 degrees, so the problem is on the right side now. There seems to be no problem from the bottom till the red post-it.
Side-with-red-paper-1.jpg
Side-with-red-paper-1.jpg (129.11 KiB) Viewed 2766 times
Red-paper-from-bottom-1.jpg
Red-paper-from-bottom-1.jpg (90.09 KiB) Viewed 2766 times
Then I removed the red post-it paper and took another picture from the bottom - this is with no eyepieces.
No-eyepiece-from-bottom-1.jpg
No-eyepiece-from-bottom-1.jpg (94.54 KiB) Viewed 2766 times
To me this seems to be a problem inside the left ocular.

apochronaut
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Re: AO Stereo Star Zoom 580 Help Needed

#6 Post by apochronaut » Mon May 03, 2021 1:48 pm

Anything rattle at all in the left mirror housing? The microscope is a pair of compound microscopes with a an air apaced doublet lens at the bottom and another compound lens in the head aperture, separated by a set of travelling lenses in the parallel zoom tracks. The bottom element is cemented in and I believe the very top element too, although it has been a while since I had one of those heads apart. Top could be all threaded set rings. The bottom main objectives are mounted and centerable in a common lens carrier. Each objective is compound with the upper lens set in by a threaded ring and then the lower one cemented. I have seen an instance where a microscope lost the bottom cemented element on one side. It is hard to tell because it is quite thin. The symptoms were similar to yours, although I doubt it would project a similar looking image left and right from a coloured card right on top of the zoom track and based on your photos, the image of the bottom zoom lens looks to be the same on each side. With a missing bottom objective lens, when looking through from the bottom : when the zoom system was at 1X, both systems would project it's smallest image of the lower zoom lens. The intact lens system projected a larger image than the one missing the lower main lens element. One was about 3/8", the other about 1/4". Importantly , the ratio between the images of the bottom zoom lens changed during zooming. As the microscope was zoomed, by the time it got to 2X the image of the lower zoom lens through the intact lens system became huge, larger than the diameter of the bottom lens aperture,and with further zooming, going out of focus. The image of the lower zoom element viewed through the partial main objective did not change over the entire extent of the zoom travel, staying the same size and in focus. Maybe just check for that condition.
Once that has been ruled out, I would assume possibly a lost lens element from the back objective element. To check for that, with your trinocular port cover off and your polarizers out, put something like the end of a small flashlight turned on or a piece of newsprint with type on it : something you can illuminate a bit and determine magnification , under the back lens element...just under the head and then on the other side and look down through the ocular tube without eyepieces. The magnification should be around 2X , the actual amount unimportant but they should be equal.
If there is a problem, hopefully you can find the missing element.
Normally, you have to remove the zoom knobs to get the zoom section out, so you can get at those large ring nuts that fasten in the mirror housings but sometimes you can get them off through the trinocular window A small but reasonably long punch can get them free and then they spin off easily. They need to be tight going back on in order to assure collimation and the washers make sure of adequate slippage and clutching. I wouldn't touch the lubricant if they are rotating fine right now.
Each comes off independently but if the microscope has not been cleaned it might be time to take both housings out and clean the mirrors, lenses and optical windows.

mhfan
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Joined: Sun May 02, 2021 6:30 am

Re: AO Stereo Star Zoom 580 Help Needed

#7 Post by mhfan » Tue May 04, 2021 8:32 am

I did the test you suggested. I used a print with the same font instead of the red colored post-it.

From the bottom, at about 1.25 zoom the left is smaller than the right.
From the ocular, without eyepieces, and the paper turned around, both sides look about the same.

Attached left:
Left.jpg
Left.jpg (84.66 KiB) Viewed 2708 times
And right:
Right.jpg
Right.jpg (72.99 KiB) Viewed 2708 times
This means that the zoom part is missing the thin lens?

apochronaut
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Re: AO Stereo Star Zoom 580 Help Needed

#8 Post by apochronaut » Tue May 04, 2021 12:31 pm

Probably. Look very carefully at the very bottom objective lens. You should see a lens with some threads exposed around the outside. The front lens is in fact cemented in. The threads are for a set ring that seats the upper lens, behind it. If the lower lens is missing, you will see a black set ring and a few more threads will be exposed on that side.

mhfan
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Joined: Sun May 02, 2021 6:30 am

Re: AO Stereo Star Zoom 580 Help Needed

#9 Post by mhfan » Wed May 05, 2021 7:55 am

I think I found the problem.
The bottom lens was fine, but as I compared each moving lens from left to right, one side of the top moving parts is missing (pictures attached).
Left-piece.jpg
Left-piece.jpg (61.17 KiB) Viewed 2662 times
Right-piece.jpg
Right-piece.jpg (61.86 KiB) Viewed 2662 times
Unfortunately I did not find the detached lens inside the body, so it seems someone else lost it before me.
Now where can I find a replacement for this? Look for another body for parts? I saw a 570 stamp on the metal parts of the zoom mechanism. Is this lens identical on a 570?

mhfan
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Joined: Sun May 02, 2021 6:30 am

Re: AO Stereo Star Zoom 580 Help Needed

#10 Post by mhfan » Wed May 05, 2021 8:12 am

Oh, and thanks for all the help and guidance apochronaut. I really appreciate it.

apochronaut
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Re: AO Stereo Star Zoom 580 Help Needed

#11 Post by apochronaut » Wed May 05, 2021 10:26 am

I don't think the zoom has too many common optical parts between the 570 and 580. It is a 4.2X zoom compared to a 6X zoom. The upper lens is the one that moves to complete the zoom cycle to 6X, so it would likely have to be a more highly magnifying lens. I suppose it could do it by travelling farther. I have not directly compared the two. I have both here, so I will have a look.
It shouldn't be too hard to find another derelict . Maybe check inside again. If the lens picked up some grease off of the zoom mechanism, it could be stuck somewhere concealed. I have had that happen. :o Presumably you never heard anything inside but that is a very small lens and could easily hide.

Scarodactyl
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Re: AO Stereo Star Zoom 580 Help Needed

#12 Post by Scarodactyl » Thu May 06, 2021 5:27 am

I think the 580 only goes up to a higher max zoom because they needed some empty space to accept the illuminator and/or trinocular port (hence it being so much taller than the 570) so they project the image a little higher and a little bigger. The zoom ratio is the same and I think the max NA is the same too, since the 580 noticeably dims at max zoom.

mhfan
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Re: AO Stereo Star Zoom 580 Help Needed

#13 Post by mhfan » Sat May 08, 2021 8:23 am

I took apart the body again and I looked carefully for this small optical element. Unfortunately it's not inside the body, so someone else lost it.

Does anyone have an AO/Reichert 580 body for parts? I just need this optical element to replace it in my body.

PeteM
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Re: AO Stereo Star Zoom 580 Help Needed

#14 Post by PeteM » Sat May 08, 2021 5:26 pm

Steven - worst case -- I suspect you might find one of the entire #570 or #580 heads reasonably priced. Seems that heads show up far more often than the stands.

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