I helped a little bit. If you are looking for well-documented formal info, wiki is good. If you are chasing some ghosts, you will have to use a search engine, like part number of a scrap piece inside a machine. Those that post this type of info will not consider writing a wiki article for that piece. But if you want to read about electron tubes, wiki has a fairly nice collection of well-written articles to get you started with. Just my 2 cents.