Hi Wayne,

Good deal! Yes, try the years around WWII ("Victory Model" transformer, remember?)

And I'll give you the entire tube compliment this weekend.

I wish I had a schematic for this thing!

Regards,
Mark

Thanks for the photos. These old radios are really great, aren't they?

I've found lots of schematics for Emerson radios that tune shortwave bands, but most use newer tubes. Of those that used 43 tubes, I only have found model 375 so far. Any chance you could take some photos of the chassis? The more information and detail I have, the better chance I'll have of finding information.

Wayne

Stayed up listening to this until 5:30 am last night! Both the shortwave and AM too. Great!

In this email you will find additional photos - one is of a "rough schematic" I drew to go along with the bottom view shot of this mystery Emerson.

Questions/explanations:

1) One of the photos shows a red marker pointing to what I think is a cap. There are several of these near the two "coils." These components have embossed colored dots on them and are rectangular in shape. Are these in fact capacitors of some sort?

2) By the way, what are those two "coils?" Are these the antennae - one for the am and the other for the short wave?

3) Could you tell me what those two square metal things are on each side of that one 6D6? (Marked as a ? on my rough "schematic").

4) There are six tubes in this Emerson. In case you cannot make it out here is the tube compliment:

(1) Type 43
(1) Type 75
(1) 25Z5
(2) 6D6
(1) 6A7

Regards,
Mark

To answer your questions, those little rectangular parts are capacitors, you're right. They are small value caps, and would probably be ceramic caps if replaced today. The two coils you're referring to are intermediate frequency (IF) coils. They, along with those caps, resonate at an intermediate frequency.

Your radio uses a superhetrodyne circuit, which is the most modern type and uses IF amplification stages. The Superhetrodyne receiver circuit was invented in 1918 and most radios were made that way from about the 1930's on. In a superhetrodyne radio, the RF signal is converted to an intermediate frequency for most stages of amplification. That way the IF amps can be tuned to a specific frequency and optimized for it. The RF section has to be wideband, since it has a tuner and covers a large frequency range. So amplification is not as efficient as the IF stages, which operate at a single frequency. The IF stages are where most of the gain is done, and then the IF detector converts it to audio for the final audio amplification stage.

Thanks for all the information.

More questions:

1) Those rectangular caps...how do you tell the value of them?
I'm pleased that someone re-capped a good deal of this radio.

2) Now Wayne. That red wire coming out the back...I have been using that as the antenna. I attach a longer wire to it. Do you think there is only one antenna for both the am and the shortwave?

3) Also, you might not be able to pick up on this from the photos but there is sort of a piece of metal with a screw on it on the back. Might this be a ground? It almost looks as if someone added it on later.

4) Any clue on the model no. yet?

Mark

The rectangular blocks use the same color coding scheme as resistors, and the base unit is pF. Those rarely go bad though, so you probably won't need to replace them. It's the wax covered paper types that are most likely to be bad, and those have already all been replaced in your radio.

You're probably right that the red wire is the antenna. I imagine it connects to the tuner or trim capacitor. Since there is no coil antenna, it is used for all radio bands. Some radios use a loop antenna for medium wave (AM) reception and a longwire for shortwave. They almost always exit the radio just like yours - as a few inches of wire with an end exposed. You should connect a length of wire to this. I like to put a connector of some type on the end, so that it isn't just a matter of twisting conductors together. But that's just me.

Wayne

Thanks for the additional info about my radio.

This from an earlier posting:

3) Could you tell me what those two square metal things are on each side of that one 6D6? (Marked as a ? on my rough "schematic").

There is a wire coming out of one of these that has frayed cloth insulation. If I can, I'd like to address that.

Regards,

Mark

Thanks for the information. And, I appreciate your looking through the Emerson archives you have on disk in the attempt to identify this model.

I can tell you this about that 43 tube. The socket has 43 stamped on it and appears to be original like the others in the radio.

But, like you mentioned. Who knows what this radio has seen? That's part of the fun of it, right? To speculate who has listened to this radio in the past and what was heard on it.

All the best,
Mark

I know that someone listened to the events of WWII through this radio, and that it served them well. I imagine the radio playing several hours every day, bringing the news to a concerned family. Then when the allies won the war, the radio probably needed service from all its use.

In one of my other radios, there was a mud wasp's nest inside. When I dislodged the nest, it crumbled in my hands revealing some long dead wasps. I realized at that moment, that these wasps were probably alive before I was. The radio was very old, and it probably had been retired and stored in a garage or barn several decades ago. While there, the wasps took up their new home. I imagine they lived and died a long time ago.

It is fascinating to me to think of things like this as I restore and listen to these old tube radios.