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Does anybody know any alternatives for replacing the 12V/100W of the BHS Microscope. Would any third party bulb work as long as it fits the two pins of the bulb holder?

I think you can buy a bulb for the BHS on Amazon or Ebay. Here's a list of compatible bulbs for Olympus microscopes.

http://www.olympuscanada.com/seg_sectio ... atalog.pdf

It is not a very special bulb design. The same bulb fits my Zeiss universal epi illuminator and my bh2-uma epi illuminator.

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According to the manual (see page 2 below) it takes Halogen 12V100W HAL-L Bulbs

http://www.alanwood.net/downloads/olymp ... manual.pdf

These are quite common and easy to obtain: https://www.interlightus.com/light-bulb ... 100W-HAL-L

There are are halogen bulbs that look similar, fit the same socket and are rated for the same voltage and wattage. Their differences lie in two specifications. Light output measured in lumens and physical orientation.
Bulbs have different filaments, so even if the wattage consumed by two bulbs is the same, one will produce less light and more heat, or radiate the light in a different pattern. Some bulbs are designed to be in a specific orientation, either horizontal or vertical. This will affect the bulb life.
It is best therefore to choose the correct bulb #.

Phillips 7724 is one listed as compatible with the BHS in that Olympus list:

https://www.amazon.com/Philips-Halogen- ... B01DTCNENK

A good example of what apochronaut is talking about that I came across recently: OSRAM 64625 HLX vs. 64623 HLX. Both are 12V/100W GY6.35 base with the same filament position (30 mm LCL) but the 64625 has a more compact filament operating at higher temperature (4.2x2.3 mm at 3450 K vs. 4.7x2.7 at 3300 K), higher light output (3600 vs. 2800 lm), and shorter life (50 vs. 2000 hours) to match.

So far the 20 and 100 W halogen microscope bulbs I have looked up where a detailed specification of the original bulb is available have all been the high-temperature, short-life types so the cross-reference provided by interlightus.com seems a bit suspect:

75RR wrote: ↑

Sun Jul 25, 2021 5:01 pm

These are quite common and easy to obtain: https://www.interlightus.com/light-bulb ... 100W-HAL-L

Did Olympus publish any detailed specs of what they call 12V100WHAL-L?

The original bulb for the BHS was the brighter 50-hour one, with a flattened filament, and should be available under $10. Others with the same pin size and spacing/bulb/volts/watts but a longer life will work OK -- just not as bright. You do need to make sure the filament ends up centered in the holder - some cross-referenced bulbs end up too low, too high for proper centering.

I've had good luck with German (Philips, Osram, etc.) and Japanese-made (Ushio, etc.) bulbs. Bulb life has been a crapshoot with some of the Chinese replacements.

Can this bulb be used in Olympus IMT-2 scope?
I also noticed some halogens have a vertical filament, is that ok?

https://www.ebay.com/itm/124712884485?m ... media=COPY



I also plan to use this one, will it be ok? https://www.ebay.com/itm/185541988350?m ... media=COPY