Wartime Civilian Radio

[Bob WilsonParticipant @bobwilson59101]

This is a wartime civilian radio, in excess of 75 years old. I paid £10 for it on a car boot sale, and as a break from building model ships, I decided to try and restore it to full working condition.

Bob

[Bob WilsonParticipant @bobwilson59101]

[Charles OatesParticipant @charlesoates31738]

Wow, that takes me back. I can still remember the smell. Looking forward to seeing the results.

Chas

[Bob WilsonParticipant @bobwilson59101]

Yes,

They always had a distinctive smell of burnt dust. I was hooked on radio at the age of 8 when I found one in the river. Occasionally, when I find something like this, I will purchase it and try and make it work again. The worse condition, the better I like it. I found a circuit online. First of all, I got it going again (see the new looking resistors and capacitors in the image). But the wiring was so rotten and decayed, that I only dare run it on 100 Volts high tension rather than the full 250 Volts. I have now removed all the wiring, after first colour-coding the coils. After refurbishing the chassis and hardware, I hope to re-assemble it in full working condition. Maybe "mission impossible," but it makes a change from building model ships.

Bob

[Colin BishopModerator @colinbishop34627]

I used to love those old valve radios too with their beautiful wooden cases in various attractive designs and with their colourful illuminated dials labelled with all those romantic sounding commercial stations. They were works of art. as well as functional items.

There is a large exhibition of radios and televisions on display at the Amberley Museum in Sussex which is quite fascinating, in fact the whole museum is packed with interesting exhibits and it is a bit sobering to see that many domestic items a lot of us grew up with are now regarded as historical museum artitacts. Well worth a visit. Check out their website.

**LINK**/

Bob, a common reason for old radios failing was blown valves. Is it still possible to source replacements for this old technology?

Colin

[Bob WilsonParticipant @bobwilson59101]

Colin,

Valves are no problem whatseover, there are still millions of them around, even unused ones in their original boxes in some cases over 80 or 90 years old. I often used to see them on car boot sales, and built up quite a large collection for nothing. I say "nothing" because when I purchased a large box of valves, I would sell the ones I was not interested on Ebay. The last lot of about 30 valves, I paid £10 for, but sold the ones I didn't want for about £80. I am not especially interested in valuable ones, because if I dropped one, or blew it, I would feel very bad. So I sell them. I picked up three "R" Valves dating back to 1914 for £10. All three lit up, but only one worked, and even so, not very well. I was just going to keep them as curiosities, but on showing them to someone, he offered me £150 for all three, even though I made it clear that two didn't work (apart from lighting up) and one worked but was very poor, He was delighted with them. I prefer the "dirt cheap" valves like in the receiver shown abouve. Unused ones in their origial boxes are about £5 each. Old TV valves such as EF91 and EF80 etc are often to be found at £1 each on Ebay, although postage is usually 2 or 3 pounds. It is good mental exercise getting these old sets to work again, and even the restpring them visually is an interesting job. Just what I needed after the aggravtion of repairing the damaged model of the barque Gulf Stream.

Bob

[Paul TParticipant @pault84577]

Ah yes the smell of burnt dust and singed eyebrows, the first valve TV that I repaired threw me across the room.

[Bob WilsonParticipant @bobwilson59101]

It is moving along very well now, this was it this morning, but since then, I have cleaned and sprayed the chassis, fitted the mains isolation transformer and the 6.3 Volt LT transformer, aerial terminal, speaker socket and reservoir/smoothing capacitors. Heater wiring commenced.

Bob

[Charles OatesParticipant @charlesoates31738]

Blimey, you don't hang around do you. I'm curious about how old transformers are after all these years, any safety problems?

Chas

[Bob WilsonParticipant @bobwilson59101]

I have never had any trouble with old transformers. They are usually soaked in wax and covered in shellac and are probably safer than modern ones. I have now put the transformers in. The large isolating high tension transformer under the chassis, 240 Volts in, 240 Volts out, that just isolates the set from a direct connection with the mains. The 6.3 Volt transformer for the valve heaters is a modern one from Maplin, and is mouted on top of the chassis. The chassis itself is earthed.

Bob

[Bob WilsonParticipant @bobwilson59101]

The power supply section has now been wired up, and is working. The 240 Volt isolation transformer was connected to the reservoir capacitor via a cheap silicon rectifier that only cost a few pence. This converts the alternating current into the direct current required to power the set. The original set had an extra valve to perform this service, and it was mounted on top of the isolation transformer on top of the chassis, making the whole thing look a bit ungainly. So, I have deviated from the original design and in my view improved on it. This may bring about "screams of anguish" from purists, but these sets are not exactly rare. The strange glow in the bottom right corner is from a small neon lamp. I incorporated it to let me know that a potentially lethal voltage of 250 Volts DC was lurking under the chassis. It seems to me that most electric shocks were sustained when the victims forgot the equipment was switched on! I do not know why all sets did not incorporate this simple indication of danger! The three valves have had their heaters wired up to the 6.3 Volt, so that they all light up. The next task is to wire up the first valve, that is the frequency changer. Bob

[Colin BishopModerator @colinbishop34627]

What sort of case would it have had as wartime wireless?

Colin

[Bob WilsonParticipant @bobwilson59101]

Coiln,

It was pretty basic. In fact it was the radio equivalent of the Liberty Ship. Here is a link to the model that I have: **LINK**

Today, I wired up the frequency changer stage (the first valve). Without any problems, I found that it was running between 1 mHz and 2.5Mhz that sounds about right for its frequency coverage of 545Khz to 1.5 Mhz. The sets cost 12 pounds 3 shillings and 4 pence when new, but by 1950, they could be picked up for less than £4. Recently, their value has shot up to between £50 and £100, depending on condition. I am not aiming for a perfect restore, as I don't like the arragement of the rectifier valve on top of a large transformer. So I have put the large transformer under the chassis, and the valve heater transformer on top. I have dispensed with the rectifier valve and used a small silicon diode rectifier instead. But future owneres would not have any problem putting it back as it was supposed to be.

I am finding it very theraputic.

Bob

[Colin BishopModerator @colinbishop34627]

Interesting link Bob, I rather thougt it might look something like that. Quite expensive though, would be around £500 in today's money. I see what you mean about mounting the valve on the transformer, I suppose it helped reduce the case footprint.

Colin

Edited By Colin Bishop on 04/11/2018 19:51:28

[Bob WilsonParticipant @bobwilson59101]

Their arrangement does not reduce the case size though. There was room under the chassis for me to place the transformer. There was also an empty hole in the chassis that could take a valveholder, but not used. So it looks like they may have initially planned to have had the valve on the chassis. I used the hole for the reservoir and smoothing capacitors (both in a single can). In the original, these were under the chassis. Even so, there is plenty of room under the chassis for me to complete the wiring.

Bob

 

Edited By Bob Wilson on 04/11/2018 19:06:13

[Bob Abell 2Participant @bobabell2]

A very interesting project, Bob

Is it worthy of housing your nicely restored radio inside one of your famous model glass cases?

Being a nut and bolt builder, to me, a valve normally controls air, gas or oil etc I can't understand how an electrical valve actually works?

They look so complicated inside

Bob

[Bob WilsonParticipant @bobwilson59101]

Thanks Bob,

At the moment, I am by no means certain that it will ever work again, although the signs are promising with the power supply and frequency changer stages working OK. If it were in a display case, it couldn't be demonstrated, so if it is successfully restored, it will be in its wooden case again, looking externally as it was 75 plus years ago. Here is the under-chassis wiring of the power supplies stage and the freqency changer stage – I have re-routed some of the wiring to tidy it up a bit – Bob

 

Edited By Bob Wilson on 05/11/2018 10:26:14

[Bob WilsonParticipant @bobwilson59101]

I completed the wiring late this morning. On connecting the aerial and loudspeaker, it did start to work, but not very well. It was very faint, and all I could hear was the station whistles with a bit of distorted speech and music mixed. in. On checking the wiring, I found I had inadvertantly left off the screen decouplig capacitor from the screen grid of the output valve. On putting it in, the volume increased considerably, but it was still quite unstable and whistling and howling most of the time. After a further hour going over the wiring again, and pondering over the matter, I noted that I had not earthed the screening pin of the intermediate frequeny amplifier valve (V2 – EF39). Immediately I earthed it – IT LIVED! . More than adequate volume with no whistling and howling. Very stable, with plenty of stations, including a French station, and what sounded like an Indian station, that was probably a relayed broadcast.

Too dark for photographs, but I am delighted with the performance.

Bob

 

Edited By Bob Wilson on 05/11/2018 16:30:00

[Colin BishopModerator @colinbishop34627]

Better check it isn't picking up broadcasts from 1944 Bob!

Colin

[Bob WilsonParticipant @bobwilson59101]

I have heard of old broadcasts coming back after many years But have never come across any myself! Here's hoping! Still some things to do on it. Make a new tuning dial, clean up the case etc, but the hardest part is now over!

Bob

[Bob WilsonParticipant @bobwilson59101]

Here is the completed under-chassis wiring. I ran it again this morning and found the performance in daylight is still excellent, with a number of different stations, all of more than adequate volume. The selectivity and tone is also very good. There is still more work to be done with the re-instating of the slow-motion tuning drive, and repainting of the tuning dial. I have been told elsewhere that doing something like this is very easy, but I can't say I have ever found it so. There are usually all sorts of problems along the way, and things as simple a omitting a single component, or earthing point can make all the difference between success and failure. In this case, the successful outcome has been of great satisfaction to me.

Bob

[Bob Abell 2Participant @bobabell2]

Hi Bob

I see you have the Home frequency, but what about the Light programme?

With Dick Barton at 6 .45 pm!

Followed by Paul Temple, once a month

Not forgetting……Valentine Dyle……..The Man in Black

Bob

[Empire ParkstoneParticipant @empireparkstone]

Funny how nostalgia dulls the negatives a lot of money for the HT battery and regular trips to get the accumulator charged and rent a replacement. I use to take it on the tram imagine doing that today ah! those were the days

[Bob WilsonParticipant @bobwilson59101]

I used to listed to Dick Barton, Journey into Space and Dan Dare, Pilot of the Future. I think they were on Luxenberg, this set does not get Londog wave of 1500 metres –

Bob

[Empire ParkstoneParticipant @empireparkstone]

only Dan on Lux Bob t'others on the beeb the daftest thing we had a nation of listeners listening to Educating Archie A ventriloquist and his dummy

Edited By Empire Parkstone on 06/11/2018 19:16:58

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