[Mr. Carlson] has an old-style 1940-era radio tube tester, the kind that used to inhabit grocery and drug stores. It is in amazing condition and he was kind enough to tear it down for us. The tester is a Model X from the Radiotechnic Laboratory in Evanston Illinois and, like [Mr. Carlson], we were amused that one of the indicators on the device is a Ouija board-like “doubtful” reading. When it lights up, it looks amazing.
This is much older than the old “TV tube testers” we remember as a kid, but the idea is the same: you have a bad radio or TV with tubes in it, it is a fair bet that the problem is a tube. Even if you don’t know much about electronics, you can carefully remove the tubes, drive over to the drugstore, test your tubes and buy a replacement for any that are bad. Uniquely, this tester even had a speaker you could use to listen to the tube’s output while testing.
