Illuminator for Bausch and Lomb Phase Contrast Microscope

[Jomar]

I am looking for some help/ideas on how to light a Baush and Lomb Phase Contrast Microscope I recently bought used. It was missing the illuminator which goes at the base of the scope (see cylindrical void in photo). I believe the scope is a Dynavision or Dynoptic based on an article I found along with an owners manual.

I used to perform PCM analysis of air samples but I didn't learn a lot about the PCM scope I used. I am new to this forum and microscopy in general so I really could use some help.
I was wondering:

• if I may be able to find a used illuminator for the scope or a budget replacement illuminator?
• Can I just buy a replacement Bausch and Lomb 18 Watt bulb (or LED light bulb) and put it in the cylinder where the bulb holder used to go? I assume I'll need to convert AC to DC and perhaps control the voltage?
• Would an led flashlight suffice for the time being until I find a suitable illumination
• Or perhaps someone could suggest a different DIY solution for lighting the field?

My 14 y.o. son is really interested in biology and science and is excited to try his hand at microscopy so I want to try to get him going. I see some modern day illuminators have a dedicated power supply and can cost several hundred dollars. I also saw 18 Watt replacement bulbs for the Bausch and Lomb scope on Amazon for $30ish so I'm a little confused. Is there something I'm missing? Is the light source more complex than just "X" watts at the frequencies of incandescent light or "Y" watts at led frequencies?

I believe the original illuminator is shown in the attached screenshot along with a diode-type replacement which looks like it has a huge transformer with cooling fins. I'm assuming the diode type retrofit may be an older technology?

Any help or insights would be greatly appreciated. Thank you.

John

[PeteM]

It looks like you have the base lens and likely the mirror.

The basic idea in LED replacements is to put the LED die (the bright bit) in the same position as the original tungsten filament. You might find a bright LED flashlight with either 3 brightness levels or a dimmer that will fit the hole at the back with a bit of a bushing around it. This might be the cheapest way to get illumination, short of buying a spare B&L stand or a bespoke illuminator like the RetroDiode.

I've even used LED gooseneck table lamps with a narrow shade and bent them to work as temporary replacements, if you happen to have one of those and want to test the illumination.

[apochronaut]

Phase contrast requires a fairly precise illumination system. Moreso than BF. One can get lucky and achieve passable results with a retrofitted illuminator but one can also have a failure.

I'm pretty sure this is the original illuminator socket for your microscope. https://www.ebay.com/itm/MICROSCOPE-PAR ... Sw34FVBbWB

Silo surplus, always puts more money on what they are selling than they think they will realize, if they put make an offer in the listing. I have bought about 20 items from them over the years and have never paid more than 1/2 of their listing price, sometimes 1/4. I would offer 30.00 on that and they will come back at about 45.00.

The transformer you need is this one. https://www.ebay.com/itm/Bausch-Lomb-Ca ... 78ee63538d
Search Bausch & Lomb transformer and you will find many others, at slightly higher prices, some almost new. You could also buy one with the Nicholas illuminator mounted on top. You can plug the microscope into the transformer or if you want to use the Nicholas for using the low power objective with incident illumination, then plug it in instead. One with the illuminator would only be about 30.00.

The bulb you need is a 1630. They are being sold by Grainger for peanuts https://www.grainger.com/product/GE-LIG ... 1630-6VF72
There is also the 1460, which looks and mounts identically. I think the only difference is a slight difference in filament shape, if any. The original spec. may be for the 1460 but I see listings where the 1630 is used interchangeably.

[Jomar]

Thank you all for your help. Great information and greatly appreciated! Hopefully i can get this rocket (um... microscope) lit.

Now if I do get it lit that's when the fun will start. I have a lot of research to do. First I thought I would clean everything (base, optics, lenses, etc.) with alcohol and then I assume there's all sorts of collimation? alignment? other things to set up to specs? Anyone know if there is a good guide or article for PCM setup/calibration? I'm a mechanical engineer so I enjoy technical things but I know absolutely nothing about microscopes other than some very fundamental optics given in physics (just enough for me to screw things up).

Thanks again.

John

[75RR]

First I thought I would clean everything (base, optics, lenses, etc.) with alcohol and then I assume there's all sorts of collimation? alignment?

Cleaning a new to you microscope that has been around a while is a good idea - zero it so to speak.

I mostly use isopropanol and cotton swabs on the lenses. Don't skimp on the cotton - never use a piece twice.

Dust is the main enemy, always keep it covered when not in use.

Collimation without instruments is a problem. Don't over dismantle.

https://microscopy.duke.edu/sites/micro ... scsope.pdf

https://archive.org/details/APracticalG ... ollimation

[apochronaut]

Your microscope has a 2:1 zoom feature. The head is fairly complicated and probably shouldn't be dismantled unless you determine that there is a problem.

Your eyepieces do not appear to be original to the microscope. They may not provide the best corrections for your objectives. They also may be a higher magnification than required. You would be best to use no more than 10X , especially with the zoom head, otherwise you will easily stray into empty magnification: an optical condition, where the magnification can be increased but with stagnant or lessened resolution.

Although it is hard to see, I cannot detect any lettering on your objectives that indicate phase contrast. Is that indicated on the objectives?