Test Equipment Anonymous

Anyway, they usually come in a fairly light proof enclosure which makes them easier to use, stops them being damaged, and would contain the mess if they were. Unsaturated - as used inside DVMs etc - yes. Saturated standalone references aren't sealed to any reliable degree. With this Cambridge Instr...

I'm fascinated to hear that Weston cells should be kept in the dark. My Tinsley cell is in a nice wooden box and is probably fairly dark inside. You'd be amazed how difficult it is to make something light-tight. Only metals stop light; it's all about Compton scattering and free electrons interactin...

Life was a lot tougher for 1920s modellers. Their lathe was highly unlikely to be electrically powered. Probably treadle. On the other hand, the materials they machined were pretty soft (which is why classic cars and motorcycles wear so quickly). But if you really want to see feats of improvisation...

You'll end up scratch building locomotives and rolling stock from the original blueprints. I've seen it happen. And that means you need a machine shop. Very useful, but expensive. Not so much these days. I came across someone building a 5½" gauge locomotive in his garage. A lot of the difficul...

What is it? An ATU - Antenna Tuning Unit.

Stay away from model railways. It's a slippery slope. You'll end up scratch building locomotives and rolling stock from the original blueprints. I've seen it happen.

There are 1 metre and 1.5 metre SDS bits. They are not particularly expensive. Aldi sell sets of three 1 metre SDS bits for £10 sometimes. They'll go through 30" of limestone wall in three or four minutes.

There are so many sketchy channels these days. I open them in a new window, and look at comments to see if anyone has immediately called them out; if not watch for a while to see how sketchy it actually is. More often than not, I find myself downvoting it, then going back to the original window and...

I have "Most Secret War" as well and don't recall him mentioning the device the video was about. What I do remember was RV Jones telling the reader just how clever he was. It must have been true, otherwise he wouldn't have kept saying so. In that case is it likely that the creator of a wo...

When I was a kid, I wondered why old people were so grumpy; now I know. If you don't become grumpy as you get older, you haven't been paying attention. The video conforms to a type which has come about recently, probably with a lot of AI involved, with misspelled subtitles and the scratchy, dusty e...

Stairs are there to be used by all and the footing should be intuitive, not like rock climbing.

It's a deathtrap.

I've seen those mains frequency meters at hamfests I didn't even pick them up :) Boxes of meters at rallies are worth a quick look over when the first pass has been done. There might be a gem, such as an HP meter of some sort, or a special for an Eddystone, Racal RA17, or Collins. There almost cert...

Yeah, I'd like one of those. But I don't want to have to clean a ham's frequency counter ;) I suppose might be interested in one of the analogue voltmeters as used as digital displays. Presumably they were used with glug-counting decade counters. I can't recall seeing one. Franlab is into weird and...

It occurs to me that a number of my teachers had probably been shot at during WWII, so sodium or calcium in water or spilled mercury were pretty small beer. I remember being impressed by physics master's demonstration of Crooke's tube where he was forcing the bungs in at each end to maintain a good...

Many years ago, there was a pick-up arm made by KMAL (Keith Monks Audio Limited). At the time, low effective mass and ultra low friction were the way to go, so unipivots were popular (especially as you can make a unipivot arm quite easily if you have a lathe). But you needed really fine wire to avo...

And then we get to exposed mercury in the home... ... and during school chemistry lessons, and in dental fillings, and a surprsing range of seafood https://www.nhs.uk/live-well/eat-well/food-types/fish-and-shellfish-nutrition/ Mercury was a mainstay of school labs. I remember an experiment which de...

I've seen a few of them around since but have never been tempted because I have no use, they are bulky, and they are usually tatty. AFAIK they didn't have a torsion wire, it was a thread of quartz. The method of making it was interesting and involved a crossbow. There was a bolt with a bar of quart...

Very pretty. Shame about the "Kelvin, g, s" legend; it must be American. I have a (very mild) hankering for a torsion wire galvanometer as used at school with its illuminated line moving a glass display. We had a Pye mirror galvanometer/µ ammeter. The physics teacher showed us the magnet ...

Sounds like a right PITA. One of those things that was a standard design, which for a few years you could buy from RS etc, but was never particularly popular, and now is a rarity. Replacing it with something more mainstream could be done, but with an awful lot of desoldering and messing about, and a...

You'll find out which one it is when you use it to repair something... Indeed, that's why they were straight into the scrap bin. I bought a big box of many, many thousands of Philips 1N4148, so I don't mind throwing out any that might be suspect. Yes indeed. I bought 200 for a quid from the slightl...

To be fair, interconnects and edge connectors are a likely trouble spot with any 30 plus year old kit. There are tarnishing problems and cables become stiff with time. I've had a couple of problems fixed by removing boards and re-seating them. Connectors will have a specified number of insertions, m...

I've just made a mental note not to buy an HP3314A function generator if I spot one.

I thought the problem was the computer detecting a power out and panicking. In most cases where a 1N4148 is used, you probably wouldn't notice if it glitched for 25ms every few hours. You might see a fleeting flicker on an analogue scope screen or something like that. Intermittent problems with 1N41...

You've got us on tenterhooks over this. Who'd have thought 1N4148s could play up like that? Have you retained them for testing to see if the fault can be reproduced outside the 3314A? As for the 1k x 4bit µPD444 static RAMs, "for almost as much as I paid for the function generator", I don'...

In my ignorance seals between different materials has always felt like a weak point, especially as metals corrode over time. Intuitively that's a reasonable thing to assume as a weak point, but a lot of effort was put into eliminating it. For instance with valves. With B9A and B7G valves (the small...

I never think of 1N4148 as things that fail. Obviously like anything else they can fail, it's just that for most applications they are very over-specified for the voltages and currents they have to cope with. You'd have to be determined to damage them by soldering, unlike germanium parts. I've never...