My advice is always the same: "first microscope? keep it simple, keep it cheap, but nevertheless: buy something usable".
This Olympus GB is, IMHO, "something simple/cheap/usable":
These can be bought here second-hand for anything between € 50 and € 100. It's an uncomplicated stand, easy to overhaull yourself. It permits the use of any optics you would like, it has a nice Abbé-condenser N.A. 1.25. It's heavy, sturdy and reliable.
These are some of the microscopes I bought second-hand over the last few years. None of those was more than 80 Euro's/US$, except the Diapan (lower right). All were in reasonable condition and ready to use, except one. Notice the build-IN 6V-15W illuminator in the Zeiss GF stand (lower middle), versus the build-ON 12V-100W HAL illuminator in the Reichert Diapan (lower right). See the text:
And if you're handy and not affraid to work it can be even cheaper. This one was for free and it turned out to be one of the best stands I ever had:
Perhaps this can help: it's a (partial) checklist on what to look for when buying a second-hand microscope.
I don't have absolute "no-no's": many problems can be solved, but sometimes it takes a lot of effort, time and cursing...
Sometimes a stand is junk, but it has excellent optics. Or the other way around.
You should take into account that having a microscope (seriously!) serviced/repaired is usually very expensive: a company here, known for their high quality work and their very reasonable prices, asks for a complete overhaul of a microscope genre Zeiss Standard 14/16 a fixed price of slightly more than 700 Euro, spare parts not included... On request they do it on an hourly basis as well: 120 Euro/hour. They do an excellent job, but well... it's not cheap.
1. A first glimpse
Brief examination of a second-hand microscope would take half an hour, up to an hour, depending on how sophisticated it is and on how experienced you are.
You're allowed to be exited and thrilled, but don't loose your critical sense! It's only a microscope. Plenty of those and there are far more important things in life.
* Microscope complete, all parts present, all same brand and same generation (do your homework!). 758
All knobs, screws, gears... present as far as one can see
* Suitcase present and in reasonable condition, key present if one is needed, factory certificate present, user manual present
* Microscope reasonably clean, no excessive dirt, no severe traces of corrosion or fungus (if fungus is present, even in very small amounts: carefully check all optics!). No excessive traces of extremely heavy use. Check aperture diaphragma dial, field diaphragma dial, surface of the stage, x- and y- dials of the stage if present, the surroundings of the focusing knobs, the nosepiece...
Spider webs and dirt on a vintage microscope, stored for decades on an attic. Turned out fine:
* Microscope doesn't spread strange smells: fungus, dish soap, cleaning naphta, white spirit, xylene, ethyl alcohol, hexane, greases and/or oils, "creeping oil" such as WD40 or CRC... A microscopes "treated" with creeping oil is about the only absolute no-no I have: these oils do what they're supposed to do: creeping in everywhere, including in the optics
* Microscope doesn't show any trace of a fall or a punch. If that kind of damage is present, decent repair should be demonstrated beyond any doubt by official documents only, excluding hearsay: repair costs estimates, invoices, correspondence between owner and insurance company if applicable etc... (observe serial numbers in those documents. They're there for a reason!)
Damage due to a drop in a Zeiss Standard microscope. A cleaning lady dropped it accidently, while cleaning a college lab. Accident and repair were well documented. Replacing it would have been less expensive, but the insurance company insisted on a repair, which was done in the Zeiss factory. Nearly all parts were replaced, except for the base of the stand, as that was considered "cosmetical damage" only. The microscope was equipped with high end optics and the price was modest. A steal:
* All adjustments (coarse and fine focussing, nosepiece, condenser height adjustment, aperture diaphragma, field diaphragma, movements of the stage, eventualy present internal magnification changers, <PERSON> lenses, polarizers, ... work well over their entire range. 626