"Cold trap is not needed on this unit (I think it is usually required for the ones with vacuum diffusion pumps) and the newer units that you see with liquid nitrogen storage use it for x-ray spectroscopy sensor (don't quote me - not an expert)."
Mostly right. The ones with the vacuum diffusion pumps didn't *need* the LN2, but it did help with absolute vacuum and helping to keep any oil contamination from getting on the sample if the backing pump wasn't perfect. There's been a general trend away from the ODP's because of the potential for contaminating the column. The turbomolecular pumps are terrific, though they can't get to quite the vacuum an ODP can on its own, though. Many of the newer scopes often don't use LN2 at all; the current generation of EDS detectors use peltiers rather than nitrogen; they switched from the old lithium-drifted silicon to solid state detectors. The old sillys needed to be below -200 to work without a metric ton of noise; the new crop of SSD's only need to be in the -30 range, which the peliters do nicely. If a newer scope does use LN2, it's usually for a cold trap.
As for biologics, the metal deposition is actually pretty easy, and the coaters can be had for not that much money. The largest recurring expense is the metal target, as it's typically either gold or gold/palladium, and costs a mint these days. Granted, you usually get 100+ 100-125 angstrom thick coatings out of one target, so the per-sample cost isn't awful. The prep steps are easy; the chemicals common and cheap.
Yeah, IAAEM (I am an Electron Microscopist). Honestly! It says so right on my business card. I'm in core EM lab for a one of the large Pharma companies. We run FEI TEM's and SEM's now, but I've lived with a Zeiss, a Topcon, a JEOL....
Your are spot-on about Zeiss making it look like they were doing production runs of 10,000's, but the electronics look like a prototype. I cut my teeth on a Zeiss 902A TEM, and it was very much the same. While it looked gorgeous on the outside, the wiring was a mess. According to what our old technician said, Zeiss wasn't very good about keeping things absolutely the same though a production run, and as they changed things....well, they just changed them. Documentation wasn't terrific, S/N splits for changes weren't always accurate, and it looked like a prototype because, in some ways, it was. That generation of scope was pretty solid, though, as Zeiss generally overbuilt the crap out of everything, both electronically and mechanically. To be fair, Zeiss wasn't the only one who had that mentality of a "production prototype". We had a JEOL SEM for about a decade, and there were hand-drawn traces in the schematic book that came with the scope. That thing was a pile of boards (and even a little breadboard) with 100 miles of wire. Worked great, though!
Zeiss's customer service is a bit fiddly; their people are supremely well trained and knowledgeable, but getting in touch with them can be a trick. You might be served well by getting in touch with Zeiss Microsystems directly. If you're in the USA, they're in Thornwood, New York (1 Zeiss Drive, no less), (914) 747-1800. I can't tell you who to talk to, though. The two techs I know there are both retired.
In my humble opinion, one of the hardest things is just getting the vacuum to hold. They leak like sieves as they age. One more place to look for a leak is the apeture holder/adjuster. We've had leaks on most of our instruments at one point or another right there. It's usually just a 50 cent O-ring, but it'll leak vac enough to cause a fuss.
Anyway, if I can be of help, let me know....and good luck with it!
-Red
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