Replacement bulbs for Carolina Biological "Wolfe" (Kyowa?) stereo microscope stand

[hans]

This thread from a few years ago is why I was thinking the manufacturer might be Kyowa? There is a small made in Japan tag on the back but I couldn't find any info about the model online. The styling on the housings containing the erecting mirrors is identical to a Unitron ZSM I have which is also made in Japan and I was thinking might be Kyowa.

I have a replacement frosted stage glass on the way from China, main problem so far is finding a bulb that fits the incident illuminator. One original Hosobuchi bulb is on the left in the photo with markings 100/120V20W JAPAN 8703. I suspect 8703 is a date code not a part number since the other one is 8609 but otherwise looks identical. My first attempt was the new old stock GE BLC on the right, hoping the 10W increase would not melt anything. The BLC fits fine under the stage (and actually the bulb holder is adjustable so it is even possible to center the filament nicely under the opening) but unfortunately it is a little too big to fit in the incident illuminator. Any ideas what a suitable replacement might be?

Otherwise it seems pretty nice. Magnification is 1X/2X switchable by 90 degree rotation of the large, coarsely-knurled ring containing the objective pairs. Build quality is good and the image is better than I expected at 1X. Compared visually to a Nikon SMZ660 there is little difference in the center but some noticeable deterioration towards the edges. 2X is decent but diffraction artifacts are visible. The SMZ660 doesn't show similarly obvious diffraction until about 4X so I guess the NA of the 2X objectives on the Wolfe is fairly limited.

[MichaelG.]

It may be worth browsing here: https://www.bulbworks.com/microscope.php

Alternatively … have you considered changing to LED ?

MichaelG.

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P.S. __ This [different model] looks encouragingly similar in design
https://artsandculture.google.com/asset ... Qlaw3m2DQA
Edit: __ and here is the direct link to the museum page:
https://collection.maas.museum/object/371503

[MichaelG.]

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Please excuse the digression …
I have just found this interesting article about making a Dark Field illuminator for the Kyowa:
https://jm.copernicus.org/articles/5/12 ... 2-1986.pdf

MichaelG.

[hans]

It may be worth browsing here: https://www.bulbworks.com/microscope.php

Thanks, the advanced search is helpful, this looks like a close match:
https://www.bulbworks.com/light-bulbs/MA2201

Unfortunately it seems like 120V bulbs with the double contact bayonet bases are pretty rare, most are 6V or 12V. BulbWorks wants more for one bulb before shipping than I paid for the microscope total. Maybe that's why there was only one other bidder...

Alternatively … have you considered changing to LED ?

Not really, for the reason given in your signature line. Another possibility would be to find a 6V or 12V bulb with compatible base that is still widely available and replace the line plug with a DC connector as I have already done on some of my other microscopes, will probably try that next.

I have just found this interesting article about making a Dark Field illuminator for the Kyowa:
https://jm.copernicus.org/articles/5/12 ... 2-1986.pdf

Interesting, for those not inclined to open the article:

In the present method, a narrow beam of light from a substage source is projected between the two objectives of a stereomicroscope so that no light enters either lens when no object is present.

[hans]

Ended up replacing the line cord with a powerpole connector and getting 12 V "1076" type bulbs which have the same base. Specifications vary slightly among manufacturers but roughly: 12.8 V, 23 W, 2800 K, 400 lumen, 200 hour life. Overdriving to 14 V (28 W) gives fairly white (for a tungsten bulb) light which is corrected nicely by the blue filter in the illuminator. Also comes in a frosted version 1076IF which I thought might be good under the stage. And they appear to still be in common use for automotive applications so not too expensive -- 3 each (clear/frosted) of CEC brand bulbs plus tax and shipping from bulbtown.com was $12.95 total. One problem, the orientation of the filament relative to the base is such that the filament ends up perpendicular to the stage. Luckily it was not difficult to loosen the circular crimp holding the bayonet receptacle to the rest of the lamp holder by prying with a screwdriver, then rotate it 90 degrees.

Both steel ruler shots are with the 1X objectives, full FOV with the camera lens at 12 mm in the first, then the second is a 100% crop from the center with the camera lens at 32 mm.

[MichaelG.]

Excellent result, Hans

MichaelG.

[hans]

Thanks Michael, it is sturdily built but not too heavy, should be nice for the kids to use. Quite a bargain as long as we don't include any hourly rate for all the time I spent scrolling through pages of light bulbs...

[Scarodactyl]

Scrolling through pages of bulbs is what this hobby is all about.

[hans]

Scrolling through pages of bulbs is what this hobby is all about.

Probably a ways to go before I can be considered a master of the bulb-page-scrolling hobby, but it's a start: