What is it? (Tube Thing Found at the Dump)

I was at the metal center at my local transfer station recently unloading some scraps that have accumulated over the winter when my nephew pointed at something hidden beneath a pile of siding and said, "What's that?"

I walked over to see the glint of a few neat rows of vacuum tubes. Of course I dove in and retrieved the item; an antiquated looking metal box with a p-2-p tube circuit inside of it.

The box itself is just shy of matching the size of a 9x11 piece of paper, five inches high, and is the painted old-school gray/blue color.

The box contains a @ 2" x 2" x 4" black painted power transformer, what is either a vibrator or large relay, a small-ish inductor, a black multi-cap, and:

1) A knob; you turn the knob and two plates get closer/further apart (with huge ground straps) It appears that there are maybe three large inductors with metal cores that move in and out? It appears so.
2) Four taps on the side labeled 'BAT' 'GND' V.C.' SFLD.' and 'D.L.'
3) 6X5, 6V6, 6SQ7, Can Inductor, 6SA7 (x2), multi-air core inductor, 6ck7.

Any guesses as to what this is? I may post pics later.

...Removing the bottom of the device reveals the circuit...

A lot of motorola paper-oil caps, minimal wirewound and carbon resistors, a pot on a long mechanical shaft, and a peltier.

It appears that one would need a star key to turn the inductor cores and the potentiometer.

Are you sure that receiver has Peltier? Or may be it is Selenium?

I'm not sure what it's really called.

It's a red rectangular box-like thing with six dots on one side. It says 'Solar' on the other side.

I assume they are to compensate for temperature drift, I've never designed for them in audio circuits.

Maybe 'thermistor' would be a better term?

picture?

I have it on my desk at work right now.

I'll post a picture later and let this thread sit for a day or so, but someone saw it and knew what it was within a few seconds...

Now I'm tempted to go back to the transfer station and find the rest of it :!:

Hint: If you can see this image, the case sort of looks like this. I think the one I have is an older model judging by the tuning method.

Here's one on eBay. Mine's much cruder looking. (if you can see it)

[quote author="beatpoet"]I have it on my desk at work right now.

I'll post a picture later and let this thread sit for a day or so, but someone saw it and knew what it was within a few seconds...

Now I'm tempted to go back to the transfer station and find the rest of it :!:[/quote]

Well, what the hell is it then...

Wow, a semi-digital anerositer! I haven't seen one of those for years!

> someone saw it and knew what it was within a few seconds...

But you won't post a picture of YOUR box here, just some other "sort of looks like" box.

The 6-dot blocks are capacitors.

I have no idea what a 6ck7 is.

"two plates get closer/further apart" sounds like a book condenser. However your "eBay" photo shows a plain rotary tuning condenser.

It is a vehicle "trunk-mount" radio receiver, obviously, but beyond that.... insufficient data. The "SFLD" tap suggests it might really be an under-dash unit, even an AM radio from a 1933 Chrysler. (Ah, but 6V6 marks it as post-1937.) Often the dash unit was just knobs, with flex-shafts to the actual radio pot/cap.

> three large inductors with metal cores that move in and out?

Of course; but are they user tuning control or technician alignment? Not clear from your words.

Classic home AM radio used the rotating condenser tuning. Mature car AM radio used fixed caps and sliding inductor cores to pick a station. Early car AM radios and police/taxi radio could be either way. But probably not both. Unless you found a combo broadcast/police receiver which was user-tuned on AM and fix-tuned for the police channel in use.

Where is the output transformer? Feed the grid of 6SQ7 (the Volume pot) for a fine funky 2W audio amp. Have to patch around the field-coil, which could be hi-Z or low-Z in vehicle radio.

[quote author="beatpoet"]I'm not sure what it's really called.

It's a red rectangular box-like thing with six dots on one side. It says 'Solar' on the other side.

I assume they are to compensate for temperature drift, I've never designed for them in audio circuits.

Maybe 'thermistor' would be a better term?[/quote]

Mica capacitor?

I was kidding about Selenium, since your thingy has 6X5 tube.

If it has an output tranny connected to 3'rd pin of 6V6 tube you may build a small guitar amp..

It should have also a tranny to convert 6V to B+ voltage (the receiver from ePay has a vibrator for such a purpose), but it is not usable anymore. You'll need a power transformer for your guitar amp.

This superheterodyne has 3 - gang variable capacitor and 6SK7 RF stage. Probably it was a receiver used by police or firefighters (they used AM band around 2 MHz AFAIR), since Motorola always supplied such agencies while RCA, Zenith, etc.. supplied radios for consumers' market.

[quote author="mediatechnology"]
The rectifier in the foreground is not selenium but the rear two are.[/quote]

This time I read your fine print before arguing! :green: :green: :green:

[quote author="beatpoet"]I think the one I have is an older model judging by the tuning method.

[/quote]

Like this?

dude you just described an Uranium PQ-36 Space Modulator. you use it to blow up the earth or any other planet that blocks your view

Illudium Q-36 explosive space modulator. get that straight. you would want to order the wrong thing!


http://video.google.com/videosearch?q=marvin+martian&hl=en&sitesearch=

so that explains why my plan to blow up the earth hasn't worked I had the wrong device