I don't know much about the Vivitar VI enlarger, but I did find three on eBay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7587398478
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7588885193
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7589498911
You may be able to glean some information from the item descriptions, particularly for the first auction. You could also try a Web search; that'll probably turn up
something.
One other comment: If you've currently got a condenser enlarger, the color enlarger may have some use simply because it's probably a diffusion model, which is likely to have somewhat different characteristics with respect to contrast, sharpness, and the extent to which scratches and dust are prominent in enlargements. Of course, this assumes you can easily fix whatever's wrong with it. If you're lucky, it'll be something simple like a bulb needing replacement.