The mystery device in the OP is a MacGuffin.
With enough voltage to cook something. It is an egg MacGuffin.
Pictures aren’t clear enough to see. If those are a bank of relays it might be to power a coil gun. There aren’t enough caps to be a Marx generator. Possibly an ignition device for fireworks, special effects, or maybe even for controlled blasting. Or it could be a Hieronymus machine.
How many external leads are there (aside from the power in)? That could help to narrow things down. Like, if it’s controlling a pyro array, you’d expect a bunch of different leads.
What confuses me is, how competent was the person who made this thing? On the one hand, it’s complicated enough that most hobbyists wouldn’t even have attempted it, and the plexiglass casing indicates at least some awareness of safety issues. On the other hand, though, I’d expect even a hobbyist to use color-coded wires, with a neater layout.
Thanks. 6v is just plain weird. Also, there should be more markings than just 6v. The transformer has 8 connections, and even with the blurry pic, there look to be a range of taps.
So, you got the numbers of ICs? That would be useful. Decoding them if you are not used to it can be a bit hard as the numbers are often a composite of standard numbers and a prefix that can be manufacturer specific, so you can get led astray for even the simplest of devices. Plus there will also be a date/batch code. I’m going to bet it will be something as simple as a quad opamp and dual flipflop in the two ICs. (There are a zillion ways to build what I suspect the basic device is, but devices with either LM or 74 in their name are a good bet.)
The circuit sure looks like a conventional push pull driver, a pretty basic one really. But using one to drive a transformer is a common trick. The Transistor numbers would be a hint if they were anything much other than garden variety, as higher voltage beasts would not be used unless really needed. Whether they are a complementary pair or not is also a bit of a clue. It would not surprise me to find they are a 3055/2955 pair. About as garden variety as you can get.
[quote=“Francis_Vaughan, post:45, topic:793198”]
Thanks. 6v is just plain weird. Also, there should be more markings than just 6v. The transformer has 8 connections, and even with the blurry pic, there look to be a range of taps. [//quote]6v secondary wouldn’t be that weird (assuming a standard 110v input). But true, that’s really not enough information if it has that many taps. Maybe the “6v” part is just labeling one tap, and the other labels are hard to see or just got overlooked?
Yeah, in post 23.
ECG4040 is a National Semiconductor manufactured 4040 CMOS 12-bit ripple counter*, which seems damned odd for a high-voltage application. 7945 is kind of useless without a prefix; as you say, it could be a manufacturing date code (45th week of 1979). Or maybe it should have a prefix: the number reminds me of an LM7900 series three-lead voltage regulator (45v negative voltage output), except I’ve never seen a 45v LM series regulator, and if the device in question is one of the DIP ICs, that wouldn’t be it. (It would look like one of the heatsinked TO-3 case transistor doohickies, not a moon-crawlie IC.)
*Datasheet is for the TI equivalent. PDF warning.
Is it meant to do anything, or purely decorative? Given you got a waveform out, it probably has a purpose. Does it do what it’s meant to do? Doubtful. Those look like electrolytic caps, which have limited lifespan (they slowly evaporate). Looks old enough that the caps probably aren’t in spec anymore. Do the caps have any other writing on them, a voltage or something?
Are some of the caps connected to ground, and others connected to incoming voltage? That could be a frequency-tuned filter (tee or pi). Or, it might be smoothing out a really noisy power line.
That circuit board looks symmetric enough that it probably is converting + and - from the transformer to + and - equal somethings, anywhere between ±6 and ±15 would make sense for old opamps (or other dual supply amplifier). Would the switches make this something that can generate +6 or -6, depending which way it’s switched? (note - remember that just because the meter face says volts, doesn’t mean it didn’t get repurposed to show something else).
The wires aren’t quite all white. Thicker white on the transformer (possibly a 2-wire bundle, separated with an exacto knife except for a couple spots?), with a single small piece of yellow wire. Thinner wires going to the circuit board.
Who built it & when? Ditto Chronos’ comment on the builder. Has a fuse, with penicled-in text no less. I don’t know how long people have used plexiglass boxes, but that is pretty professional standard for what I’ve seen in the last few years. Looks like heat shrink tube on the wires going into the circuit board. On the other hand, those crank handles look like something from the seventies.
I would say either a skilled amateur working from a kit, or a college student building something from the lab. Too much self-preservation protection to be a shocker (fuse is good, 4A fuse not so much). Possibly ham radio-related? Would explain big caps arranged as a filter. Otherwise, a power supply for something else scratch-built - van de graaf (probably too complicated for that), laser flash lamps, plasma-y halloween display? Something that needs repetitive pulses.
Gnoitall: I would expect low voltage chips on the control side, high V is only in the amp. Single-side power supply when there’s dual on the board is odd, and a 20V rated part seems higher V than needed.
Prototype for a 1920s style death ray
Is there enough room for a cat in the box?
You win the thread. 
IANA EE, but way back when I did a bunch of hobbyist electronics. This was my reaction. A borderline insane combo of smart and stupid, sophisticated and crude.
The terminal strip on the one edge (Post #30 Pic 10) has 12 leads coming in = background plane and only 5 going out = foreground plane (1 blue/black + 4 red). I can’t see any bridging clips so the other 7 leads are dead ends.
Why does the strip even exist? Is it a patch panel of sorts and moving the various output leads to different inputs gives different waveforms?
Is there perhaps a connection between it being a 12-lead strip and the 4040 IC being a 12-bit counter? Maybe they’re tapping certain bits to get certain multiples of the IC driving clock freq, whatever that may be.
I hope the OP’s pal was smart enough to stand well back the first time they powered it up remotely. There’s definitely lethal potential (heh :)) in this diabolical mystery engine.
Hahahaha!
Looks like the conversation has rapidly escalated above my pay grade, but I’ll soldier on and do my best.
There is no actual lead out to the scope. My friend attached the scope lead to a wire at some point appropriate to capture the signal. The only things that protrude from the plexiglass box that did NOT have knobs on them are the two shafts coming out of the ignition coil. One is hollow, but does not appear to be a socket for a jack, or threaded, or anything; the other shaft is solid but has a shallow depression on the end as if to accomodate a screwdriver. (it’s not a deep cut like a shaft has for a knob.) Oh yes, and the light switch.
The plexi box itself it very well made. All the seams are joined, not bent; every hole accomodating externals is so perfect as to appear molded rather than drilled. There is no commercial brand or label on it.
The components and wires both appear to be a mix of both old and newer components and wire. This I think tends to suggest it is not a kit, as a kit would certainly have color-coded wires and all contemporaneous components. So probably a meticulous hobbyist, or it’s a prototype of some kind?
The box when turned on makes a high-pitched squeal of a very complex nature, a pulsed repeating pattern, and the parameters of this sound can be adjusted considerably with the three shafts attached to pots. There is another shaft that had a knob (before we took it out of the box) that when turned makes a chunk and then turns within a range of motion. This also affects the sound; it appears to switch it to a different, lower frequency range.
I’ll go email my friend right now and ask what the transformer and transistors say.
The ignition coil outputs are standard - that’s how old ignition coils connected to the distributor.
Clearly (to me), this device was designed to create high voltage pulses at a variety of repetition rates and waveforms. They WHY is a different story - it could be almost anything - Plasma Globe, Kirlian Photography, Plasma discharge speakers, some medial woo device - who knows?
The capacitors and transformer are on the primary (and control circuit) side - the capacitors are just part of the power supply filter.
Email sent. Meanwhile, here is an excerpt from an email he sent me last night:
- I wonder why the designer used ic’s for the oscillator rather than just a straightforward analog circuit. This tells me that it was designed by a person with modern electronics training or knowledge as I would have maybe used a coil-cap circuit or a 555 timer chip which is kinda old-school. It is interesting that that some of the parts were bought surplus (the large value 200 volt electrolytic caps that hada dollar price tag on them as an example). The knobs and the pot shaft couplers were very old as were some of the pots and the power transformer that could have been from the 40’s military surplus. The wire-wrap and perf-board goes back to the 60’s and the fact that no printed circuitboard was used says that it was a prototype or maybe one-shot effort. The wiring is very good and tells us that the builder was a skilled electronics person but did it on their own time because if it were for a company all the parts would have been new. Again, your observation that the wires to that terminal strip could just have been soldered on tie-strips or just together told me and obviously you that they they were that way for a reason, like maybe they might need to be changed at some point.*
beowulff: Kirlian photography! You guys amaze me. That was my friend’s first guess. So we looked up a scematic for the apparatus for that, but again it was actually a simpler device than this.
(FWIW, even the radionics devices I’m familiar with have less going on inside than this thing does.)
So, I wonder why the parts protruding from the ignition coil are just sticking out like that, considering that the one shaft will bite you pretty good if you accidentally touch it when the box is turned on. Seems like they were involved in the function, else they’d be covered or something.
It’s clearly part of a Proton Pack used for weakening hostile manifestations.
Okay, he says:
The power transformer is an R-949196-1 military filament transformer with two 6 volt
secondaries. The two heat-sinked power transistors are 2SD 822. There are some other transistors and diodes as well. The IC’s are 4040B and 7945 which seem to be the oscillator parts and the discrete transistors the amplifier for driving the coil as we surmised.
This reminds me of one of those stories where an alien or time-traveler gets stranded in a less high-tech time and has to build something using near-random crap in unique ways–E.T. with his communicator, Doc Brown with his steam-powered time machine, an episode of SG1 were the guy builds a stargate with stuff ordered off the internet…
When this thing was turned on, did you notice any unusual windows to a different time or place opening mid-air nearby?
This device looks like something I would have built in my “high voltage” days - when I was in High School in the late 80’s. I would bet that this is of a similar vintage - the computer capacitors are the right era, as well as the dual-secondary filament transformer. Even the TO-3 transistors and heatsinks are the right age. I wouldn’t be surprised if this was based on (or inspired by) some Radio Electronics or Popular Electronics magazine article from 1970-1985 or so.
Another vote for homemade shocker.
Ha ha,
"This week in Popular Mechanics, 'Energy Weapons for the Gentleman Geek.'
**‘How To Win Friends & Influence People (without really frying)’
**
**‘Dadaist Death Rays: the Road Less Travelled’ **"