Old? Yes! Useless? Maybe.
I've never operated one of these monster machines, but I have seen them. They are excellent for certain puposes.
Aside from the fact someone would buy a machine ("optical comparator" - correct spelling) he didn't know how to use, your situation is not much different from that of any organization where the sole operator of a specialized machine dies or quits without passing on his knowledge.
(I never learned how to program one of our CNC turning centers. In fact, I would have had to read the operating manual just to figure out how to turn it on. I was lucky. We had lots of skilled folks who did know.)
The first thing here is to greet you: Welcome to the Cove!
The second thing is, don't panic.
Third, here are several options for you, depending on your product, your customer requirements, and your urgency:
- If no one in your organization has ANY experience with optical comparators, You can advertise for someone to come in and operate your machine who DOES have experience.
- You can survey machine shops in your area for someone who has operated a big 30 inch screen comparator like this to come in and moonlight to train several employees to use it for your specific need.
- You can take a general course at a technical college (google - some even have internet access to take an on-line course) on the general concept of using optical devices for inspection.
- Ignore the comparator and use an alternate method to inspect your product.
Next, I'm curious about your product and what you need to inspect that you think you need a used optical comparator to perform the inspection. Typically, the best use of an optical comparator is with a specially etched or marked "chart" which can be either frosted glass or a translucent or clear overlay sheet to put on the screen to compare the part or a feature of the part to the drawing, measurement, radius, angle, etc. on the overlay chart. The technical term some use for the chart is "reticle." Here's a company that makes them so you can see what I mean
http://www.reticles.com/comparators.htm (this is only one of hundreds of sources.)
If you don't have such a chart for your part, you need to have one made.
I'm looking forward to learning more about your situation.