Vintage Car Radio Information Needed
 

Does anybody know any information about this car radio?

http://img.photobucket.com/albums/v2...s/100_1495.jpg

http://img.photobucket.com/albums/v2...s/100_1496.jpg

PS Sorry I don't know how to resize images on here.

What does the speaker label say? What tubes are in it? It should have a 6 Volt vibrator.

Since the tubes are octal, it brackets it from about 1939 to 1948 more or less.

It does sort of have a Buick look to it.

It might a pre-war Chevy radio, built by Crosley. The missing vibrator should be next to the 6X5 tube.

I was looking through Rider's. I remember seeing that control layout. I'll look at the Oldsmobile schematics next.

Thanks for the help, I'll see if there is a label in it. Is there any value to this radio?

Says Utah speaker and Chicago thats all I can make out 3.2 ohms

I don't think it has much value, as ugly as it looks. If you restore it, well then maybe. Lots of rust, can't read the dial, etc.

I revise my date estimate to prewar, maybe 1938 to 1941. Probably a 6K6 audio output, 6K7 and 6Q7 and such.

I see the radio has a 6X5 rectifier tube. With all the problems those tubes caused in 1930s Zenith radios (shorts that took out the power transformer), I wonder what could happen to a car radio if the tube shorted, since of course there is no transformer to contend with. The short could drain the car battery, damage or destroy the vibrator, or overheat the wiring under the dashboard and/or under the hood near the battery to the point of starting a fire, :yikes: if the fuse under the dashboard did not blow first.

I guess thats why they made replacement vibrators back in the day....:scratch2:

I'd be a lot more concerned about the short starting a fire under the dash and/or near the battery. Replacing a vibrator is an easy fix, and there is no damage done to the rest of the car (the underdash fuse would hopefully blow if the vibrator contacts were to weld shut); fixing the often horrendous damage caused by an under-dash fire (if not caught in time), however, would be a lot more work and potentially dangerous if the fire were to reach the fuel tank. :yikes:

BTW, I wonder why this car radio even had a rectifier tube in the first place -- after all, a car battery supplies DC voltage as it is. Why rectify the input voltage twice? :scratch2: I also wonder why a 6X5 was used in this particular radio, rather than a 5Y3 or some other tube with a better track record as far as internal shorts are concerned. Personally, I'd rather go without a car radio than have this firetrap in my car. I wonder how many underdash fires and/or fatalities occurred during the time frame when these radios were in use in vehicles. :scratch2: I hope not too many.

There was several different reasons why this proceedure was followed. The old cars only had a 6 volt system. There was no tubes that would work on that low of a plate or screen source. That 6X5 was no more troublesome that any of the other rectifier tubes, for that application. Philco used 7Y4 or 84, depending on the year. Some larger radios used syncronous vibrators that rectified by means of commutating contacts.
Government equipment used genemotors, as they didn't trust vibrators.

From how I understand it most tubes needed more than 6V (or 12 in newer cars) for the B+ supply. A Vibrator form how I understand it is like a relay wired so that every time it's coil de-energises the contacts close and re-energise the coil. Thus causing it to oscilate. Coils detest sudden changes in current and create a large magnetic field to fight/counteract the change, so if you put a suitable secondary coil in the field generated by the current pulses you can harvest non-sinusoidal AC power from the field to feed the B+ circuits, but it must first be rectified and filtered just like any transformer type home set.

And that is why rectifier tubes were used (though i've heard of self-rectifying vibrators which may or may not have an internal rectifier of some sort).

And that is why rectifier tubes were used (though i've heard of self-rectifying vibrators which may or may not have an internal rectifier of some sort).[/QUOTE]

That's what I was refering to. The vibrator was large and had another set of contacts to do the rectifying. They even used them the Zenith farm sets.

The rectifier tube was probably for reverse voltage protection in self rectifying sets. After all if the rectifying part of the vibrator went bad and AC or reversed DC hit the lytics without a second tube rectifier to stop it the lytics would end with a bang, and an alarming (to the average consumer) amount of smoke. I don't know how the other parts would react to AC or reverse voltage, but I'm gonna guess it wouldn't exactly be good.