I was not there, Gandalf. This was before even my time.
It tests vacuum tubes that would usually come from televisions. If a tube was bad you could hypothetically replace the tube and get your TV working again. The various holes are for the various tubes that were sold.
Vacuum tubes would eventually be replaced with transistor designs as transistors were more reliable and required way less power to operate. Also they were vastly smaller than tubes. Today most TVs are, in essence, a small computer packed into a single chip called a System on a Chip (SoC), so they are way less user repairable. But they’re also vastly cheaper than the 1930s versions. In 1939 RCA’s TV that they sold went for ~$600 or about $13,280 in today’s money.
So there was a ton of incentive to make TVs as user repairable as possible. It’s also why we used to have a lot of TV repair shops that we pretty much have zero of today. Putting that much investment into something, you’d want to make it run for as long as possible.
Love your description, but I would add that radios were arguably an even more common reason for people to replace tubes. Also, while television stations did exist as far back as the late 1920s it really wasn’t until after WWII that it became semi-common for the middle class - I live in Denver and we didn’t get our first station until 1952, for example.
The furniture-style console TVs still had tubes as late as the 1970s.
We had one very similar to this until about 1980..
It was easy to pop the back off (it had little hinges like the back of a picture frame) and the tubes were right there. Very simple fix. You’d miss your show, but it meant a fun trip to the electronics store with dad.
Sylvania now: “Just throw that piece of shit in the trash and buy a new one”
I worked for Sylvania about 15-20 years ago as they were swirling the drain and trying to adapt to LED lighting. Lots of cool old equipment and facilities but it felt like whoever was steering the ship (Osram) was asleep at the wheel. The way the company handled the next 15 years proved that was true.
Some folks are still using tubes for audio equipment aren’t they?
Not just guitar audio! I own a tube amp for my guitar and 2 tube amps for driving my higher-end headphones! They are neat little pieces of electronics history, not just in how they run, but also because most of the best tubes are old military surplus. My oldest pair are from 1945 and were made for early army/navy radar systems.
Yes, I’m a reseller. I bought a large collection of them from a pawn shop that was closing. Some of them are quite sought after. The most expensive I’ve sold were $200/ea. Some sellers use higher end testers in order to make claims that the tubes are “matched” in their percentage of specification from new. I think it’s a dubious claim. I have a cheaper tester that says if they’re good or not. I only state that they are tested and appear to be new since I obviously have no way to know if they actually are NOS or if someone used them at some point.
I worked at a grocery store that still had one of these in the mid 90s. It had been there since the 60s but no one who worked there still knew how to use it.
Found an EMC Model 213 tube tester at a thrift shop this summer. It’s a cute little portable unit in a fabric covered hard case, from about the early 60s. Useless without the chart (typeset on a literal typewriter) that tells you how to set the row of 12 switches & three knobs that dial in the proper test for each type of tube. Luckily I found a scan online!
I’ve got plenty of vacuum tubes to test…if it still works. Who tests the tester?
