Replacement abbe condenser for Olympus CX-31

[SnowyNW]

Will any 1.25 NA condenser be suitable? It seems that the top lens of the CX-31 condensers are much larger than the CX-21 or CX-41, and older bh2 models.

[apochronaut]

The diameter of the top lens of a condenser is indicative of the size of the field that it will illuminate, if other factors of condensers being compared remain the same. ; N.A., , whether either condenser also uses any auxillary lenses and the working distance from the object being viewed. The N.A. of the condensers used in the CX 21,31 I assume to be the same, the w.d. with a 1mm slide I would assume to be the same since they are oil immersion condensers. Neither the CX21 or CX31 condenser uses an aux. lens but the BX 41 condenser does and I don't know of a 1.25 N.A. condenser for that scope. Maybe there was one.
So,
The CX 21 has an 18mm f.o.v. and an N.A. 1.25 condenser. The condenser must illuminate a 4.5mm minimum circle to cover the view of a 4X objective. That condenser is fixed to it's focusing slider. Not sure it would fit anyway.
The CX 31 has a 22mm f.o.v. and an N.A. 1.25 condenser. The condenser must illuminate a 5.5mm minimum circle to cover the view of a 4X objective, so it's top lens will be larger. Even if a CX 21 condenser were to fit, it won't likely illuminate the entire field of the 4X objective.

The CX-41 has a similar set up, with a 1.25 condenser capable of illuminating down to a 4X, so a 5.5mm minimum circle. It can receive alternate objective magnifications.

The BX 41 and has a minimum of 22mm field but as mentioned, I don't recall a 1.25 abbe condenser for it. The condensers are of different N.A.s , .90 dry, 1.1 oil, 1.4 oil. An aux. lens is used too with one so the top lens diameter isn't that relavent. If you are able to get one to fit the CX 31, a couple at least will illuminate a 5.5mm circle to cover a 22 F.N. field at 4X, so will illuminate your maximum required field. U-AC2 1.1 N.A. abbe and U-SC3 .90 swingout type. I don't know about the fit.

[SnowyNW]

Hello,
I appreciate the extensive reply. Maybe it doesn't make a difference but the bodies I am using are CX series and not BX. Here are some pictures of my condensers on my others scopes They seem mechanically interchangeable in terms of fit, but I'm not entirely confident about function. Here is the CX-31 condenser that I am using as a reference. It has a blue filter and a much larger condenser lens compared to that of the CX-41's.


I was thinking of trying one of these options as a replacement:

https://www.ebay.com/itm/304695000332?m ... media=COPY

https://www.ebay.com/itm/296196195795?c ... 1&mkcid=28

[apochronaut]

I'm sorry but I wrote that really fast out of my noggin, which might have been sleep deprived and I meant CX. so just replace the B with a C. I'm pretty sure all else is accurate. Edited for accuracy now.

[SnowyNW]

Of course, should have occurred to me. Just realized my CX-41 condenser in the above photo is also a 1.25 NA. Maybe its from another scope?

[apochronaut]

CX-41 uses 1.25 according to the manual but the CX-41 can accept other objectives. Aside from fit, there are height and focal length concerns with a condenser, plus it's capability to accept an aux. lens for very wide fields. The 31 and 41 are the same frame and illumination, are they not?
I am wondering what is wrong with the CX-31 condenser you have?

[SnowyNW]

I'm currently servicing a CX-31. The condenser shown is from another scope. Unfortunately this one has no abbe condenser and needs a complete replacement. Do you think this one would be adequate if it fits? https://www.ebay.com/itm/304695000332?m ... media=COPY

[apochronaut]

Are the centering screws not integral to the condenser on those two CX's?

[SnowyNW]

They are, I can't find a single condenser for sale third party or otherwise with the secondary attachment at the bottom. I'm not even sure what its called

[apochronaut]

37mm sleeve?

[SnowyNW]

Are you referring to the required condenser measurement or the one in the listing link? I've measured my sleeves and condensers to be closer to 36mm

[apochronaut]

Olympus , for some reason went back to an older condenser sleeve mount for those microscopes. It's anyone's guess why but imo , the reason is pretty transparent.
Their previous mount was 36.8mm. I was just trying to confirm if they used the same as previous or have they used another dimension. If you can get a really accurate measurement for the CX 31, that will help find a solution for you.
I used 37 above just to get in the ballpark. I know 36.8mm seems odd but Olympus inherited some Imperial dimensions in inches from Bausch & Lomb during the Occupied Japan era and just kept them, converted to odd metric measures.

[SnowyNW]

Well both of them are closer to 36mm if not exactly that, do you happen to have a replacement or know which will fit?

[apochronaut]

I'd prefer to see the thicker, inside part of those jaws fully over the condenser barrel. Can you put a metric ruler or scale across the i.d. of the sleeve and see what you get as well. Not the caliper, a scale or ruler using the 10 as zero because sometimes that first mm on tapes/rulers are not accurate.
How much more than 46 do you get?

They may have just gone with off the shelf components that the mfg. supplied, so not adhered to their old standard as well.


Some factory or factories in China made the CX line and still is. Could have been Motic as one of them but there are numerous brokers selling them out of China. Many of the broker companies are actually manuufacturers too but maybe not of microscopes. Some are. Since Olympus has discontinued the "1" series and replaced it with the "3" series, the "1" series may still be made in China or at the very least parts might still be available and at about 1/4 of what Olympus would want.
You could try contacting these people in the link below as a start and see if they can supply a condenser. Sometimes, the posting is old and they will try to steer you toward buying the new model, in this case it will be the CX-33 but since you just want parts, they may be willing to help with that.
I once went looking for a trinocular head for an older Chinese model that LW Scientific used to sell, maybe 15 years ago. The microscope itself was listed at around $1500.00 F.O.B.out of Ghangzou. A decent research model . The LW version was infinity corrected and the Chinese version, which was the same microscope with just a more heavy duty illuminator and one more objective, was listed as 160mm but the Chinese listings often have errors. The head was identical and less than 300.00 for a 23mm trinocular with eyepieces but the sales agent at the factory insisted that the info. was correct and that it was 160mm. Didn't want to supply it in case it didn't work. Just to show that customer service is alive and well in some places.

Have a look here and there is even one without a condenser. Maybe they are holding it for you? And a couple of SUPMYLO 13 XC forced to exist, trapped in a mirror.
Giving them a shout might be worth a shot. Don't worry about all the descriptors and errors. One gets used to that with the Chinese style of marketing.

https://icenteco.en.made-in-china.com/p ... scope.html

[SnowyNW]

Thanks for all the help, I'll definitely explore the above option.

Do you know why the cx-31 condenser has a blue filter while the cx-41 has a clear lens?

Could I take a phase contrast condenser from a BH-2 and use it with my newer CX-31?

[apochronaut]

With both having a 30 watt halogen bulb, both would benefit from a little absorption of the longer wavelength part of the spectrum, so a blue filter is valuable for both. The 31 was more for student use so perhaps they just wanted to make it very straight forward. The 41 had several condenser options so allowing the filter to be placed in situ. for each separate condenser would just save money, plus not everyone agrees that a blue filter is desirable for BF and it isn't necessarily for certain applications, such as fluorescence, so leaving it as an optional accessory makes sense.

The question of whether you can use a BH-2 phase condenser on a CX-31 is a little more complicated because the BH-2 has a finite optical system and a dovetail condenser mount. I suppose you might be able to adapt it but there is still the problem of having no centering screws plus the issue of whether the condenser diaphragms would at all conjugate an image with the annuli in Olympus infinity phase objectives.

In your case, there is no particular reason to be choosing an older Olympus condenser from other disparate Olympus microscope systems over any other condenser. There is very likely a very limited family resemblance between Japanese Olympus microscopes and Chinese ones. Olympus even sources parts from other Asian countries, possibly Thailand and it is questionable what percentage of the specifications are generated from Olympus or o.k'd upon submission to Olympus. A direct question from me by email to Olympus about that received an " Olympus has suppliers and mfg. facilities in many countries ".
The way to choose one should be based first on a physical fit , then once that is intact, an optical fit. Does it cover the required field and is it tall enough to touch the slide?
Are you sure it is exactly 36mm or a little more as is the case with older Olympus sleeve condensers?. If it is in fact 36mm, then I would be looking for 36mm sleeve type condensers with built in centering screws. Those will more likely be found on other Chinese made microscopes that were designed based on the same parts supply. A lot of the average grade Chinese microscopes were designed based on selecting from available pools of parts supplies, so many microscopes that on the surface might not seem the same, can have some or a lot of the same components. I can't see why Olympus would have tooled up to make a few unique condensers for the CX-31 and 41, when they could buy off the shelf condensers from Chinese jobbers much cheaper. They may even buy components from Carton Optical in Thailand or India.

The case of a phase condenser would be similar and if you are intent on converting your scope to phase, this is the time to do it, since if you get a phase system applied to that scope, the condenser will also work for BF.
Do you know if there is something about the CX-31 that inhibits it from using CX-41 condenser systems? If you can make a CX-41 phase condenser work on that scope, why not see if one of the Chinese suppliers of the CX-41 will sell you a phase package : condenser and objectives?

[SnowyNW]

That's a really good plan, I'm currently negotiating for a CX-PCD Turret, and I guess it will now become a phase contrast scope. Considering the cost of infinity corrected phase contrast objectives I have been dreading this moment for a long time haha.

So far I've been collecting microscopes to try and find the most affordable approach to each viewing method. Right now I have a complete trinocular Olympus CK2 with phase objectives up to ULWD CD PLAN 40 PL complete apart from the phase annuli which I will attempt to manufacture myself if I can determine the optimal proportions, and also without a photo objective, and an additional CK2 body lacking a lamp housing with a burnt out transformer on the board which I used for spare parts, which also has an entire set of PL objectives. This scope is really handy for water samples and mycology, but lacks the ability to resolve above 40x I believe due to the condenser aperture?

I also have a Nikon Eclipse TS100 inverted scope, which has significantly better optics than the CK2, but I only have a 20x ph2 objective for it, since Nikon objectives are aberration corrected I find them to be much harder to find for affordable prices.

As for upright scopes I have a CX-21,31, and 41 with a spare 31 and 21 for parts which I've been fixing up and have basically returned to complete but I only have four complete binocular heads and one broken one. Three sets of Plan C bright field objectives which came with each working scope. I've found repairing scopes to be a lot of fun, and very similar to my bikes and cameras.

Lastly I have a very old Olympus FH binocular scope with a phase contrast condenser, a set of older short barrel phase contrast objectives and a set of the newer DPlan objectives.

Initially I was planning on using the infinity corrected cx scopes, but was unsatisfied that the cx-21 didn't provide Kohler illumination so I upgraded to a CX-31 and CX-41 only to find out neither is really equipped for DIC.

Instead of going for a BX, I think I'll either try getting DIC for my FH if possible, or save for a BH-2. I was planning on choosing one inverted scope for water samples and phase contrast, and an upright scope for DIC(eventually). Any advice? I'm now thinking stick with the Nikon, broken ck2 to experiment with an LED conversion, and either the FH phase contrast with the short barrels(which according to Alan wood are still excellent) or this CX-31, or both if I can afford the objectives. Any advice? Will I be able to recoup any money from the cx scopes? They seem relatively undesirable.

[apochronaut]

Pete M knows a lot about DIC setups , particulary Olympus. Maybe he will chime in.

[SnowyNW]

Would you happen to know if the U-PCD turret will fit the cx-31 and cx-41?

[apochronaut]

Dovetail mount ? You know this reference I guess?

https://www.alanwood.net/olympus/microscopes.html