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LED Illuminator for LOMO МБИ-3
i.e. MBI-3 Vintage LOMO Biological Research Microscope LED Conversion |
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By Dushan Grujich, on October 6th. 2013 |
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LOMO MBI-3 Biological Microscope |
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LOMO MBI-32 Microscope was produced during 1950's through 1960's
Biological Research Microscope TL 160 mm, equipped with OI-14
aplanatic condenser 1.4 NA, with binocular attachment accompanied with a
set of matched eyepieces, with a set of apochromatic objectives (shown
in the table below) and a
plan/concave mirror. An optional illuminator OI-19 can be used to
provide Koehler illumination.
This stand has served as the basis for development of the Biolam 70 series microscopes two decades later. |
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I was asked by a local vet to do maintenance check, adjustments of the microscope and to do LED conversion of the microscope. One of the repairs needed was a typical failure of OI-14 condenser top lens element, which by now has for me become a routine operation. The LED conversion was done by applying the same principle I have used to convert the LOMO OI-321, except in this case there was need to fabricate the housing as well. |
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The image above shows the housing and collimating lens mounted on top |
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| I have managed to solve the problem of the new housing by taking a short piece of aluminium pipe 50 mm OD, with wall thickness of 2 mm. Out of aluminium sheet of 2 mm thickness I have cut cover to press fit the top of the housing. On its top side I have mounted the collimating lens which also serves as a holder for star diode, firmly holding it to the top cover, which also serves to provide additional heat sinking. | ||||||||||||||||||||||||||||||
| The electronic module, KIS-3R33S, is mounted inside the enclosure soldered to a piece of breadboard, securely fastened to the bottom side of the top cover by use of brass spacers and two screws. Miniature potentiometer, incorporating the on/off switch, is mounted onto the outer side facing away from the observer while the 3.5 mm receptacle for the wall plug-in unit is mounted on the side. as visible on the photo above. | ||||||||||||||||||||||||||||||
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Instead of a collector lens I have used a 30� collimator lens which nicely and fully illuminates condenser, easily checked with phase contrast telescope |
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Here we can see the illuminator under power firmly sitting in its position without wobbling or danger of disconnecting |
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Photo above shows the intensity control pot, 12 V DC receptacle and the arm which serves to securely mount illuminator instead of mirror |
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Another view of the illuminator and illuminator plug |
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