I recently discovered the Antique Radio Forum. I hadn't cared much for web-forums; too insular and too painful to browse to keep up with the new posts. But ARF has two things going for it: a very knowledgeable community, especially in the test equipment area, and a nice mix of photos and text in the posts. The photos really add a lot; they're what's missing from the technical email lists like the qth-boatanchors list.
While reading the ARF test equipment forum, I stumbled on a post from Paul Koby looking for a manual for a Cushman CE-21. I've got one too, also sans manual. I bought it at the Deerchester hamfest back in the '90's for $125. Works fine, but someday it's going to need servicing. So I approached Paul and we agreed to split the cost of purchasing a manual from Manuals Plus; I'd scan it and send him on the original. So I'm liberating the manual; I've placed my scan of it in my local archive here and will pass it on to the other manual sites.
(Hmm, BAMA doesn't take test equipment any more; where's the current canonical repository for liberated test equipment manuals?
Answer from ARF: Ebaman and Didier's site.)