Will these condensers take a drop of oil? I assume they do but would prefer to be sure in case they could be ruined. Is there a way to tell?First question:
And also, brushed upon in other posts, is there a way to retrofit or add light to a common microscope to boost the wattage? My system used a 6V 30W halogen bulb and it seems that the need for more light could be part of the reason my scope does not get better DF. And maybe even Rheinberg. Perhaps overall design comes into play also. It seems especially obvious with the cardioid.
Responses no. 5 and 6 down the thread, see photos of the parts of a cardiodid condenser, by 75RR and myself, respectively; mine is a Zeiss, though somewhat different than yours. The "heart" of the cardiodid (pun) is a sealed unit, that is fitted within a round shell that consists of several parts and rings, and there are no o-rings or other elastomer seals. Hence, in principle, oil laid on the top surface might crawl and leak inside, between the heart and the shell. It happened in my condenser once and I suspect it happens every time I use it, especially since my immersion oil is Type A, which is not very viscous. Yet, since the condenser is designed to tolerate oil, I fear not. Moreover, some of the black coating or paint has been peeled off my condenser, and I bought some modelling matt black paint to re-coat it, but did not do it yet. I will report when done.Second question:
more light is always a benefit, provided it does not warm up the other parts of the scope and specimen. For example: on a certain Olympus scope, 20W halogen is very good, 50W has melted the plastic fixtures and damaged the base. If the lamp is external to the microscope, behind it, it will be easy. If the lamp resides within the base, and you stick with halogen, be careful. LED retrofit might be the best way to go, PROVIDED that the LED is very bright. From my experience, for the cardiodid, a 10W LED is the absolute minimum, and 20W may be even better (depending on the distance of the LED from the collector optics) ; 3-5W LED is too dim IMO. Most DIY LED retrofits on the web have been limited to LEDs of 1-5W, I think.
There are at least two suppliers of tailored LED retrofits for old microscopes, one in Texas and one in Germany or the Nederlands, and the prices are roughly 150 USD.
May I suggest, if you consider conversion to LED, that you post the scheme of the optical train of the microscope, if available.