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On Monday 04 November 2024 03:27:22 am wn4isx wrote:

I've seen a 2N2222 used in avalanche mode to drive a xenon strobe. It feels as though they used the C/E connections across 120 with a series resistor and capacitor similar in how a NE-1 relaxation oscillator was wired. When I saw it I didn't believe it possible. This would have been the summer of 1976 because a local company was making xenon strobes for a local Bi-Centennial event.

I couldn't believe the low parts count because I had constructed a xenon photo strobe for my father.

I never heard of an NE-1, which I thnk you've mentioned more than once. I know NE-2 (wire leads), NE-51 (bayonet base) and the H (high brightness versions) of these. I also recall NE-45, which was a screw base with a built-in resistor for 120V, I had an old tape recorder once that used a couple of these for level indicators. I thought they were kinda nifty, but the last time I looked the pricing on them was silly.

On flash units, at one point my brother was working for a photo processing place. I got him to snag me some of the flash units that were removed from those disposable cameras. Aside from a brief look, I have't taken the time to figure these out. There's a pair of battery contacts (which polarity?) for a AA cell, and two sets of switch contacts, one to turn the flash on and one to trigger it, but reverse engineering them is something I haven't gotten around to yet...


--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

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On 11/4/24 23:10, Andy wrote:

You might want to insure it doesn't have PCB. Many highvoltage capacitors
used that crud.

Polychlorinated biphenyl is often called PCB. Scary stuff
according to the Wikipedia article about it.

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That's funny because my first exposure to a dictionary was one from Encyclop?dia Britannica? -- and the associated set of encyclop?dias didn't give me much training in American spelling either.

Donald.

On Monday 04 November 2024 04:09:10 pm wn4isx wrote:

Somewhere I have GE light bulb manuals [in PDF] from 1960ish. NE-1 were wire lead with no resistor, today the NE-2 looks to be the same.

On my server I'm pretty sure I have the "GE Glow Lamps" manual. If it's not on my web site I can put it up there.

Try a Google search for "Neon NE-1 bulb."

My father bought me 500 from Burstein-Applebee when I was 10. I still have more then I want to count.

I remember that company, though it's been a really long time since I've thought of them. Are they still in business? Why 500 of them? Neon bulbs can be fun. Certain organs that I worked on used them in frequency divider stages, and sometimes the vibration in the console of the lower notes would cause a lead to break, giving a missing note, or several. In those units you could take out a couple of screws and swing the chassis out into a horizontal position, and it was easy to observe which bulbs didn't light when you pressed keys. I always wanted to get some of the ones that it up in different colors because different gases in them. Like some VR tubes do. I'd probably play with them some more if I had a suitable power supply, but haven't so far felt motivated to build one.

On those salvaged flash units, there are two types, most were (?are?) small xenon strobe tubes, probably have a life of no more then a few hundred flashes, the other uses white LEDs.

These all have the flash tubes. How do you figure they have such a short lifetime?

The ones with the xenon strobe will have a ~300uF 300~400V capacitor that will light you up but good.

That cap is very apparent on these units.

Been there, done that and still feel the zap. I mean be careful with those tube ends and capacitors! They have enough energy to stop your heart. Use the "keep one hand in your pocket" technique.

Look up " xenon strobe circuit diagram" on Google for examples of how they are constructed.

Unless you need a really bright light that lasts a 1/1000 of a second, I'd be really tempted to send them to the electronic recycler.

I figure to play with 'em one of these days.

I no longer work on tube guitar amps because of the high voltage. I've worked with 24V and less for most of my professional life.

My brother is very much into tube guitar amps, for the sound of them. I have a power supply and amplifier chassis and speakers out of an organ that was scrapped, and my intention is to make a guitar amp out of that. One of these days.

1V of video won't fry your ass. [most of my professional life revolved around 1V of video and 0dBv of audio]

Marshal made an amp with 1200V at 500mA B+.

I very much doubt that. Maybe half that much. I used to be a Marshall service center, and probably still have schematics around here someplace.

We had a tech get zapped and stopped breathing. We managed to get him breathing but it was a way too exciting 5 minutes. The boss buttoned up the Marshal and told the customer, "We don't work on these."

Sounds to me like he got careless...

I suspect many (?most?) members in this group have limited education in electronics and fail to appreciate all the dangers.

Back when I was into messing around with chemistry experiments I tried electrolysis, but found operating from batteries (which were probably prett much at the end of their useful life anyway) to be abysmally slow. So I took a selenium rectifier that I had handy, rigged it up with a line cord, and was very pleased with the results. I had to keep adding water, and was surprised at how dark the water got after a while. Put me off of drinking tap water for a good long while, that did. I was probably 11 or 12 at the time,

I strongly suggest purchasing a "stand alone" Ground Fault Interrupter/Residual Current Sensor and never work on any mains powered device that is not plugged into that outlet!

Got one of those in a short extension cord kind of format, but pressing the test button doesn't do anything. I might have to investigate that one of these days.

I used



until I had time (and mobility) to wire in real GFI outlets.

~$15 is cheap insurance.

Not something I worry about too much. I started out in electronics when tube gear was still pretty common, all over the place, actually. Ran a TV repair shop for a bit, and it was mostly tube gear in those days. I only got zapped good one time, ignoring the warning on a sticker in a zenith TV set and gouging my arm on the lip of the metal cabinet on my way out of there. That's about 25KV or so, and is probably the worst I've ever gotten zapped. One of the first bits of stuff had to do with a course my father was taking (that I ended up finishing). They had a 5x7x2 metal chassis with a 35Z5 rectifier tube and a light bulb in a socket, line powered of course. One of the things you were supposed to do with it was connect the output wires to nails stuck in a potato, and observe the different behavior near each of the nails. That things gave me a good tingle or two when I was messing with it.

Unless you know why, have all your equipment powered from the same outlet, use high quality metal power strips.

I have some power strips, but also DIY some of that stuff, outlets in electrical boxes with a line cord attached, etc.

And forget Variacs and mains isolation transformers until you understand their limitations and safety risks they can add.

Got both of those, and I know how to use them. And also how to get by without them. I can still remember one TV I was working on where if you plugged the (non-polarized) plug in the right way the chassis was grounded, the other way it was hot. So I'd check this every time I plugged it in, until the one time I forgot to do that, and damn near vaporized a ground clip of my scope....

I started messing around with radios when I was 4, crystal radio, AC mains radio when I was 7, got my ass knocked off, look up All American Five.

I don't have to look it up, I know it well. Both the octal and the miniature variants. Built one in shop class back in high school. Where I doubt very much that they even have that shop class any more.

By the time I started formal electronics education I'd survived most of the stupidest stunts one can do and learned safety the hard way.

Yup. that's how that works.

My father once told me "Son if you're determined to be stupid you'd better toughen up." This was over Sunday lunch and my family broke into hysterical laughter.

The idea of "Terry toughening up" is still funny.

Please be careful.

That's a matter of course.

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

On Tuesday 05 November 2024 07:33:55 pm wn4isx wrote:

I'm not sure an electronic organ amplifier / speaker will make a decent guitar amplifier.

I expect that beyond the power supply and output tubes (plus the phase splitter, etc.) the input end of it will be heavily customized. Maybe clone a Fender or somesuch? The project is pretty low on my list, so I haven't spent a whole lot of time looking into it yet.

Rod Elliot knows a lot about guitar amps, actually he knows a lot about audio, but used to play guitar and has a section devoted to guitar amps.

I'm familiar with his stuff, have been slowly working my way through a lot of his pages, and have corresponded with him a bit.

(snip)

I suspect an amp for an electronic organ lacks the ability to handle the clipping.

That'd be determined by the input circuitry, I think, which has yet to be configured.

Before building a case, have your brother bring an electric guitar over and check the amp for clipping on an oscilloscope.

No need, I have one on hand here.

(snip)

FWIW I play an Ibanez acoustic with an Australian piezo pickup for recording. This piezo pick up is quite possibly the best pickup for a string instrument possible.



It is significantly better then a high quality studio capacitor microphone.

I have various piezo bits in among my salvaged parts. Just for the heck of it I connected one up to my scope to show my lady what her voice looked like. I was rather surprised by the sensitivity of the thing. Easy enough to put something together if I decide to go that route. These were originally in phones, I think, to generate the "ring". But they work quite well as input devices too.

I use Elixir with Polyweb coating. The guitarists out there might investigate them.

You lost me here.

Afterthought....

If your Linux machine(s) have a good FFT program, you can isolate the output of an amp with a good AF transformer and attenuator and look at the amp's output as an FFT, clipping will jump out and smack you in the face.

If I don't have such a program, I'm sure one can be had without too much trouble.

The waveforms from a guitar pickup are not nice clean sine or even quasi sine waves. At best they are a scrambled mess. [Take a look and see.]

It's been a while, but I have looked at that...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

On Tuesday 05 November 2024 04:07:01 pm Roy J. Tellason, Sr. wrote:

One of the first bits of stuff had to do with a course my father was taking (that I ended up finishing). ?They had a 5x7x2 metal chassis with a 35Z5 rectifier tube and a light bulb in a socket, ?line powered of course. ?One of the things you were supposed to do with it was connect the output wires to nails stuck in a potato, ?and observe the different behavior near each of the nails.

I actually ran across a video that referrences this:



The guy does the potato trick with several different voltages, with varying results...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

On Thursday 07 November 2024 09:00:11 am wn4isx wrote:

Did you ever see Mr. Hotdog? [I think that was the name]
A plastic tray with stainless steel spikes that impaled the hotdot.
Close the lid, plug in to the AC mains and watch those suckers cook.

It worked there was some crude "safety" interlock that only interrupted one side of the AC.
I got knocked silly trying to load it barefoot on a concrete patio. I was 10 and told Mom, "I am not touching that thing again." And I didn't. Then a hot dog caught fire and it was fun for every one. I grabbed the AC cord and unplugged it and my father sat it well away from our home and we watched it burn.

When I was in 7th grade I took "electric shop" (closest I could get to electronics in that school) and one of the projects done there was a cooker that had a sheet metal frame, a square of asbestos about 6" or so, a couple of strips of sheet metal with serrated edges that were bolted to that, and a line cord. You could put one or several hot dogs in it. They also had spools of nichrome wire and some ceramic standoffs so one could make a DIY hotplate, but I was never quite clear as to how they figured out how much of that stuff to use.

One fun time I went in there and here on the bench was one of those photocell thingies like you see on top of a streetlight. I wired that up with a lamp in a socket that would shine on the unit, and plugged it in. The room lighting was dim enough that the light would come on, shine on the photocell, turn the light off, and so on, continuing with a rather slow oscillation until unplugged. The teacher tried to see if any of the other guys there could figure out what was going on. :-)

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

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And more OT - how many of us have played with blobs of mercury or just had some in a dish on the desk?

Donald.

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On Friday 08 November 2024 05:18:23 am Donald H Locker via groups.io wrote:

And more OT - how many of us have played with blobs of mercury or just had some in a dish on the desk?

A number of years ago I worked on a rather large machine that was supposed to assemble various plastic bits, a drop or two of mercury, and a silver pellet or two, to make cartridges for dental amalgam. I was told that the initial cost of this machine was something around $160,000, and that they'd spent between $300,000 and $400,000 to try and get it working.

There were a number of fault conditions that would stop the machine so that the operator could correct things. The nature of the fault was indicated in a little box that had a bunch of lamps in it that would project some words on to a small screen. When I first powered it up, *ALL* of those lamps were lit, because the "engineers" that designed the thing had neglected to put diodes in there to protect the solid state devices that were driving the relays. I didn't understand how they could neglect doing that...

The "logic" in this thing was on a stack of circuit boards that was in the middle of the machine, silver dust and droplets of mercury all over the place. It amazes me that it worked at all. They weren't using TTL or anything like that, it was a line of parts made by Amperex that they called "norbits", and was very simple logic, like gates and time delays and such. They kinda sorta looked like chips, but *HUGE*, over an inch across and maybe close to three inches long, and they had an odd number of pins on the package so you could only put it in the board one way. I've not run across that stuff before or since then. That logic was driven by a proximity detector (to sense the level in the mercury tank), a whole bunch of lamp/photocell pairs to sense the presence of various plastic bits, silver pellets, etc., stuff was fed into it from "vibratory feeders" each of which was driven by a small variac (!), there was a magnetic amplifier in there for the main drive, a panel with something like 28 relays to provide fault indication, and I forget what all else. Oh yeah, and the "power supply" for the electronics was a big variac, and maybe 1000uF or so of filter capacitors.

It amazes me that the damn thing worked at all.

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin