The funny thing is that it’s quite loud, even without an antenna hooked up. If it’s a quackish device, wonder if that’s a bug or a feature?
Filament transformer makes sense. It would be useful to know which way around it has been wired. If you can make out the leg numbers on the winding diagram and what they are connected to it would help.
A 4040 makes sense, as you can configure this to create a frequency synthesiser. A really easy wide range frequency control is to just select between the output bits, and connect that back to the reset. Gets you a programmable divider that goes in multiples of two. 7945 seems just plain odd. That isn’t a digital device one recognises, and given the 4040 is a CMOS device, a 7400 series chip would not seem sensible. I would expect some sort of flip flop driven by the frequency synthesiser to generate a symmetric waveform for the driver amp. Is there any chance the numbers have been misread? It could be a multiple op-amp package, which could be set up to generate the waveforms. If it were a 7495 it would make sense. A 4 bit shift register may just do what is needed. (Except for the ttl to cmos bit)
The 2SD822 confirms the need to ask. That is a high voltage device. The system looks for all the world as if it is being driven from rectified mains (Argh, never do this in home construction, it is a death trap.) So a high voltage transistor is reasonable. Two PNP devices, so a very basic (not complimentary) driver configuration. The wiring of the transformer probably dictates this.
So, it looks as if there is a mains voltage frequency driver that is driving a transformer. I had assumed earlier that there was a desire for major voltage step-up and the transformer was going to be run backwards, but I suspect it is actually run the usual way around, and the output is 12v (pair of 6v windings in series) and that drives the ignition coil. So you get a continuous variable frequency drive and pretty much the standard output voltage you would expect from the ignition coil. This won’t, by itself, drive much of a spark, and may still be intended to drive another unit - maybe a Tesla coil or similar. The variable frequency drive still seems odd.
I know from some playing with Kirlian photography a zillion year ago that the effects you get can be dependant upon all sorts of second order issues, so it may be that this device was able to allow useful manipulation of the results.
maybe it tests out Neon tubes ?
A thought: You’ve looked some at the actual function of the device (checking out the waveforms it produces), but we’re pretty sure that it’s not functioning as designed. For instance, someone already pointed out that the big capacitors are mostly in parallel, but that it looks like some connections are missing. Have you tried making any alterations like completing the capacitor wiring, and checking the waveforms then?
Speaking of the capacitors, I think someone said that they’re electrolytic? That seems an odd choice for what’s so obviously an AC device. Are there any rectifying diodes there? Is there such a thing as a non-electrolytic capacitor with the same specs, that could be substituted there (either by you for testing purposes, or by the original designer, if that’s not the same person as the builder)?
It doesn’t do anything. That’s the beauty of it.
Oh come on, someone had to say it.
I’m getting a headache looking at the pictures.
Could you get some more light on, or maybe take it outside, it so your phone can take a non-blurry picture?
Any ways, it’s odd that they are using a 6v transformer unless that ignition coil is an older one when cars had 6v DC systems as cars are now 12v DC. There is no advantage and if anything a disadvantage to driving a 12v DC ignition coil with 6v.
The circuit and pots to adjust the waveform remind me of the “dwell” circuit used for cars that have an ignition coil as you have to properly saturate the coil in order for it to produce a spark, however, the time to saturate depends on the engine RPM. Therefore, it has to be performed correctly as if you dwell too long you’ll miss and if you dwell too short you’ll have a weak spark. That’s why you have all that there, they were creating sparks of various frequency and had the adjust the circuit to properly saturate the coil in order for it to work correctly.
Why they reinvented the wheel like this when one can buy the module from any car from like the 80’s and into the 90’s if not early 2000’s for cheap is beyond me. Unless this predates the 80’s and I’m not sure of those modules were available in the 70’s. But, safe to say any car with fuel injection will have one of those modules. Then, all one would need is something to replicate the hall effect sensor off the crankshaft for engine RPM, which is really easy to do.
Uh, important safety if you fiddle with wires. If the capacitors have + and - terminals triple check connections. Backwards wiring a polarized cap = explosion. Not so bad with a little tantalum thing (funny smelling magic smoke), but something that size could spray a lot of hot dielectric.
Teccccchnically it’s an educated guess. But in my experience, large value caps (1 milli and up) are electrolytic, and the “big can” shape is typical. Interestingly, one of the first hits on a quick google was a “motor capacitor”, big silver can with screw-on terminals rated for well over mains voltage, so it would work as a powerline smoother. And nowadays, power supplies are the main place you’ll see canned caps, I guess for their voltage rating.
I had been wondering about car battery related from the size and voltage, but then variable frequency wouldn’t really make sense. Theramin for the sound, but you said you got a spark from one of the outside terminals… 
If this was for a shocker or zapper, I’d certainly call it a death ray. Still sounds like a driver for something.
Arrgh, you people are so…young.
The big caps are “computer grade” electrolytics. That’s how computer (and other equipment) power supplies were filtered in the 60’s though 80’s, before a) switching power supplies became common and b) high-value, small form-factor electrolytics were invented.
A really ugly Theremin or John Titor’s time machine.
It’s quite clearly a speculation generator.
It’s a conversation piece. It obviously works.
Ha ha, none can gainsay you.
I see that my “reputation” has fallen to negative 12 since I posted those pix on imgur. That doesn’t seem good. Having never used it before – am I supposed to be interacting in some way with a community? I tried to reply to one or two comments, but the website wouldn’t let me. (showed me a red circle/bar when I pressed the “post” button.)
For those who would like better pictures, I’m afraid I only see my friend on wednesdays. I will indeed take the box outside and try again.
One more possibly salient point is that the power cord was cut off when he bought it. That could be for a variety of reasons. There are actually people around here who cut the cords off of things left in freeboxes or on the curb, to recycle the wire. The thrift shop gleans its stock from a wide variety of sources. Or, it might have been cut off by the box’s maker to prevent us opening a portal into somewhere beyond time and space.
I think I found a use for it. (Well maybe.).
Okay my arcane-wisdom-having friends, here are the pictures in direct sunlight:
I hope these are a little clearer!
Looks to me like a home made amplifier.
http://www.geocities.ws/jojod818/leach_amp/leach_low_tim.htm
I have no idea what it is. But we have to allow for two possibilities. the first being that the mysterious builder made this item from whatever they had handy so that even though there might be easier ways to accomplish whatever this thing does (if anything) there would be parts in there that would seem to not be related to the purpose.
The second possibility is that someone, perhaps the OP, perhaps the purchaser, are engaged here in some old fashioned leg-pulling.
Ahh, a third possibility. That it is a theatrical prop, kludged together for a film featuring a mad scientist character. That’s all I got considering that someone already beat me to the “that’s the beauty of it” line.
OK a few useful things can be seen. However a few more pics - especially the wiring digram on the side of the output transformer and under the perf board - so we can see a bit of what is going on would be useful.
However - we can see it probably has an input transformer and the bottom LHS rotary switch is the power.
The ICs on the perf board are a 4040 (shift register) and a 4030 (quad XOR). The XOR is a bit hard to fathom, it isn’t the obvious thing to use, but there is probably some method in the madness.
The rest of the perf board remains looking much like a conventional push-pull circuit. There appears to be the usual driver transistors plus a variable bias. A few more transistors than I would have expected in the input, but given the high rail voltages I suspect are there they may well be needed - possibly cascoding a current mirror drive from a differential pair. Looks as if that is possible anyway. One of the controls on the board is probably output bias. It is sitting next to what I suspect is the bias transistor.
The output transformer is I bet, a filament and HT transformer. These are incredibly common, and it was probably pulled out of some old tube based military device. 6v is not as common a voltage for filaments as 12v, but both are use. I suspect it has two 6v windings, and the old orange jumper between two lug on the transformer as left over from its original use, where the winding were used in series to get 12v. That would account for 4 terminals on the transformer. Then you get 2 input terminals, and two HT output. Terminals 5&7 are fed with the input, and 1 and 8 the output. But there is no standard about how these terminals are allocated, so without the diagram on the side it isn’t possible to work the rest out.
It is interesting that the meter has been hand labelled to read +/- 15 volts. That suggests that this is reading the drive to the ignition coil, and that the circuit is designed to allow for precise drive to the coil. In particular it may be that it is intended to provide for both positive and negative going initial waveforms, or perhaps that the meter is designed to make sure that the drive is symmetric.
Had a bit more of a look. (I can’t help myself with such mysteries.)
The little transformer under the top control plate seems to do nothing but provide a single voltage, used by the potentiometer next to it to set a voltage. It is desperately awful. A total bodge job. Half wave rectified with a diode stuck up in the air, and terrible soldering. I have a feeling the meter is simply reading the voltage off the potentiometer. So something is voltage referenced. Maybe it sets the output voltage for the driver.
I can’t see any rectification for all the big caps except on the perf board. Yuk. I’m back to thinking the mains is direct rectified to supply the power drive. The big caps are simply off board, and connected back. Despite being a seriesed pair of parallel caps, there is no 0v point taken off them. Which probably isn’t needed as the entire thing floats about. I have the awful feeling the CMOS chips are fed via a large dropping resistor. The resistors are out of the ark. I haven’t seem 10% carbon resistors for decades.
The construction quality is very amateurish. Enthusiastic kid level. Lots of flux everywhere, bodged up joints,. overcooked bits. Clearly a few repairs on the way. Parts seems to be all surplus or recovered junk.
The thing is worthless, and I would be very hesitant to ever power it up. The transformer is maybe valuable to someone messing about with tube driven guitar amps. Some of the mounting hardware is nice and beefy too. The rest is skip fodder.
If it were a theatrical prop, it wouldn’t do anything. But it does: It produces a high-voltage signal. A prop designer would have no reason to actually wire up high voltage. Unless you mean that it was powering something on stage, like a Jacob’s ladder or plasma sphere or something, but then this thing’s purpose would not be as a prop, it’d be powering a Jacob’s ladder or plasma sphere. Except that that seems not to be it, either.
Prototype flux capacitor – go stick it in your Chrysler Town and Country and visit the 1600s.