Ethan Reigns
Scooby
You know you are old if you remember drug store tube testers with a selection of the most popular tubes in the pedestal under the tester. There were no settings or controls - you just plugged the tube into the appropriate socket (of about 80), waited for the tube to warm up then read the number off the meter. If it was zero, the tube was dead. If it was low, the tube emission had gone down to the point where a new tube would be beneficial. You could fix your own radio or TV if the problem was just a tube.