Posts Tagged With: Valve

ScrapHappy October 2022: Someone else’s Scrap…

A relic from a bygone age - not so bygone now!

A relic from a bygone age – not so bygone now!

Now I may be wrong (I usually am, it is my default state) but I think that one can rejoice in someone else’s ScrapHappiness and, indeed, claim a little of it for one’s own. So, before anyone puts their hand up to raise an objection, here is this month’s offering which comes in the form of a kit from the National Museum of Computing (NMOC), here in the UK at the legendary Bletchley Park.

First, the scrappy bit of this – this is a kit of electronic bits and bobs that when correctly assembled, makes a thing. Technical, I know, but I’ll explain later what the thing does as that isn’t important right now. The nifty bit about this kit is that it uses a type of electronic component that is pretty much the first type of active electronic component ever devised by humans. It is a (thermionic) valve, and not the “ooh, there’s water leaking out of it” kind but the “look, it’s glowing” kind. The real scrappygoodness (that is a word, I know, I just made it up) is the valve. It’s a piece of scrap, lying around unloved and, more importantly, unbroken. Where did it come from originally? Well…

Way back in 1955, the UK decided that one television channel (BBC1, then known as the BBC Television Service) was insufficient and that another one was needed. Cue ITV, which would be transmitted on a whole new band of frequencies so high that, well, your average TV set couldn’t receive them. Genius, I know, but you have to remember that there weren’t that many TV sets in the UK at that point. I’m going to guess around 12, but there may have been more. Anyway, in order to use existing TV sets to show the new-fangled ITV, a set-top box (“Band III convertor”) was built that would let that happen. And it did.

And you won’t be surprised that most of those set-top boxes were scrapped a few years later. It would appear though, that many ended up taken apart – they had two useful valves in them and I am guessing there were lots of people who would use them to build their own electronics.

Many decades later, and NMOC have a large stock of these valves, salvaged from defunct set-top boxes (and other places too). They designed this kit to give these old valves a new lease of life, and raise much-needed funds to run the museum.

An OK Valve

An OK Valve

There is something almost alien-looking about valve tech

There is something almost alien-looking about valve tech

Finished and Working!

Finished and Working!

I built the kit – it was pretty easy and the instructions were, on the whole, very clear. I had two issues, one of which resulted in another piece of scraphappiness and the other resulted in a bit of DIY-like swearing. There seemed to be a capacitor missing in the kit so I found an old one (probably out of a light bulb) which fitted the bill. The swearing was caused by the thing not working but, on closer inspection, I had put two of the boards too close to one another and they were touching, and not in a good way.

So, does it work and what does it do? Well…

Video link to where I sound like a sci-fi villain


Many other people contribute to Kate and Gun’s wonderful ScrapHappy every month – check out what they have been up to too!


KateGun, EvaSue, Lynda,
Birthe, Turid, Susan, Cathy,  Tracy, 
Jill, Jan, Moira, Sandra, Chris, Alys,
Claire, Jean, Jon, Dawn, Jule, Gwen,
Sunny, Kjerstin, Sue L, Vera,
Nanette, Ann, Dawn 2, Carol,
Preeti, Debbierose, Nóilin, Viv and Edi


Categories: General silliness, recycling, ScrapHappy, Sustainable Stuff | Tags: , , , | 15 Comments

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