Back in the late 1940s through the early '60s many small shops and general stores in North America had public tube-tester boxes, along with a supply of the most

Back in the late 1940s through the early '60s many small shops and general stores in North America had public tube-tester boxes, along with a supply of the most common replacements, so folks could save a lot on upkeep costs. For those uncomfortable with reaching into what were usually chassis-grounded televisions and radios, complete with their low-level shocks, hum, and that special vibration on the fingers when touching the metal even when turned off or unplugged, having a technician do all that for them was a necessity. Clearly a home repair service would need to charge for that value-added work. Where TV repair folks made their big bucks was in bringing the TV set into the shop for a new flyback transformer or picture tube and not on simply replacing chassis tubes.