This microscope was purchased used in 1985.

Questions:

1. Where can replacement bulbs be obtained, and is there some trick to installing them?  The bulb that was in it when purchased, was soldered into the threaded brass ring.  The back of the scope seems to say 6V, but inside, the transformer says 7.5V.  6-cell Maglight flashlight bulbs soldered into the proper place work sort of OK as replacements, but their filament shapes don't allow optimal Kohler illumination and I'd like something that does.  (See second panel of pictures.) 
   
2. Can the condenser be replaced with other models, say to provide phase contrast?  The mounting flange dimensions are 39.5mm diameter and 24.9mm depth. (See third panel of pictures.)  The current condenser is unmarked except "1,2", which  I presume means a maximum NA of 1.2.  It seems designed for brightfield only, though I presume darkfield stops can be inserted in the filter carrier.
3. Am I correct in thinking that all objectives except the 3.2X are basic achromats?  (See third panel of pictures.)
4. Is there a model name or number for this unit?  The only number I can find on the scope itself is on the condenser carrier.  It is 649669 (see third panel of pictures).
5. Where can I find documentation for this scope?  I think I've been through all the relevant stuff at http://www.science-info.net/docs/, but I may have overlooked something.
   

Thanks very much!

-- Rik Littlefield, email rj.littlefield@computer.org .