1940s radio

I'm looking for any info on this one, I've found next to nothing online. It has no manufacturer name anywhere, and no back.

It's a 3 valver with mazda octal military valves, 2x VR65 rf pentodes (aka

10E/11446 ARP36 CV118 CV1065 SP61) & a VT501 beam tetrode output (aka C V1501 E1192 10E/389).

Pics:

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The PSU is very basic, with one mains wire straight to chassis, & the other going through a metal rectifier to a reservoir cap. The knob grub screws a re more or less flush and not insulated. The output transformer is rather s mall. The tuning knob has no gearing. In all I don't think this was a good manufacturer, though it's stylish.

As far as I can tell from a quick look over the chassis it's TRF with eithe r no reaction or maybe a little nonadjustable reaction.

One of my main questions concerns the metal rectifier. 2 items in series wi th 9 large discs on each, yet this has to handle mains voltage. Is that rea lly enough for 240v ac? Or must this be a 100v set, which would be uncommon here. AIUI there were at the time areas still on 100 or 110v.

thanks NT

Reply to
tabbypurr
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First & second pic: Good old Selenium rectifier stacks; about 25V per plate rating iffinn eye member rite. 9 rectifiers * 25 V/rectifier = 225V (appx) rating.

Reply to
Robert Baer

. It has no manufacturer name anywhere, and no back.

aka 10E/11446 ARP36 CV118 CV1065 SP61)& a VT501 beam tetrode output (a ka CV1501 E1192 10E/389).

ther going through a metal rectifier to a reservoir cap. The knob grub scre ws are more or less flush and not insulated. The output transformer is rath er small. The tuning knob has no gearing. In all I don't think this was a g ood manufacturer, though it's stylish.

ither no reaction or maybe a little nonadjustable reaction.

s with 9 large discs on each, yet this has to handle mains voltage. Is that really enough for 240v ac? Or must this be a 100v set, which would be unco mmon here. AIUI there were at the time areas still on 100 or 110v.

20v x 18 = 360v 25v x 18 = 450v so should cope with 240v ok.

The total lack of a radio anywhere on google that matches this one is odd.

NT

Reply to
tabbypurr

This is close-ish, but no cigar...

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...a Google image search for 'art deco white valve radio' shows that there must have been hundreds of designs, some of them really rather attractive.

Cheers

--
Syd
Reply to
Syd Rumpo

Those tubes were mass-produced during WW2 so may have been plentiful on the surplus market. Heater voltage is listed as 6.3V so perhaps you can work back from that to figure the supply voltage?

piglet

Reply to
piglet

** The set has a 6.3V filament transformer on the chassis - so using a Variac, you can find the correct AC supply voltage easily.

..... Phil

Reply to
Phil Allison

Yes, and I assume this makes it post-war rather than say 1940.

riac, you can find the correct AC supply voltage easily.

Yes :) I'll probably try reforming the lytics rather than replacing initial ly, though I assume the paper ones will be beyond hope. I need to fix the w iring first, someone's cut a few of the leads, but after a quick look it se ems not hard to see what goes where.

Knob insulation is an issue. I suppose it's either an isolation transformer plus earth or temporary heatshrink sleeving.

NT

Reply to
tabbypurr

ne. It has no manufacturer name anywhere, and no back.

(aka 10E/11446 ARP36 CV118 CV1065 SP61)& a VT501 beam tetrode output (aka CV1501 E1192 10E/389).

other going through a metal rectifier to a reservoir cap. The knob grub sc rews are more or less flush and not insulated. The output transformer is ra ther small. The tuning knob has no gearing. In all I don't think this was a good manufacturer, though it's stylish.

either no reaction or maybe a little nonadjustable reaction.

ies with 9 large discs on each, yet this has to handle mains voltage. Is th at really enough for 240v ac? Or must this be a 100v set, which would be un common here. AIUI there were at the time areas still on 100 or 110v.

er

dd.

-tube-type.jpg

There are a number of similarish sets from around 1940. One site also said similar things were sold in kit form after the war by unheard of manufactur ers.

It's odd that product designers can now seldom make good looking electronic s.

One thing I've learnt is this is presumably plaskon, which is very vulnerab le to heat & solvents.

NT

Reply to
tabbypurr

snipped-for-privacy@gmail.com prodded the keyboard with:

Looking at your pictures, reminds me of a kit sold by "Albion Electrics" in Leeds, West Yorkshire about 1950 ish.

--
Best Regards: 
                      Baron.
Reply to
Baron

Yes. I reckon it's a postwar radio, quite possibly a kit. And a manufacturer & model there seems to be no record of - at least on google.

NT

Reply to
tabbypurr

snipped-for-privacy@gmail.com prodded the keyboard with:

There were a number of publications around that period, 1945/6 through to at least mid to late 1950's, that described how to build these radios and TV's from military surplus. I don't remember the names of them any more. They were A5 size and had a green print front, most of the adverts in them were for radio valves and surplus kit. I'm sure that there were enterprising people that collected and sold kits of bits. Padgets on Meadow Lane in Leeds, was one, Leeds Radio was another, but someone had to spend a fair amount of money to produce a moulded cabinet like that.

--
Best Regards: 
              Baron.
Reply to
Baron

snipped-for-privacy@gmail.com prodded the keyboard with:

I recall the screws in the knobs being filled with red sealing wax and the screws in the rubber feet that threaded into the chassis treated the same. Another got ya, was the capacitor in series with the antenna. Get the mains the wrong way round and it would bite you. A lot of these radios were wired into the bayonet type plug that went into a light bulb socket, making it very easy to get the mains wrong way round.

--
Best Regards: 
                      Baron.
Reply to
Baron

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...but it would take a lot of looking.

Cheers

--
Syd
Reply to
Syd Rumpo

There's no room. The user connects direct to the mains on this set. I'll bet that's why it was retired from service.

Exactly. Or a 2 pin round pin 5A plug.

Once it's working I ought to look & see how many chassis connections there are. It might be feasible to remove nutral from chassis & earth the chassis. Otherwise it's going to have a major usability problem.

NT

Reply to
tabbypurr

Indeed, and they spent the extra to make it plaskon too. But the innards do not reflect a matching level of quality.

I assume it's British, as it's in Britain now and uses British military sur plus valves.

I plan to fit a modern speaker to a new back, the built-in one has siezed s olid, is o/c and the cone has broken up round the edges. Better than replac ing it, someone might take the trouble to restore the original one day.

Suggestions would be welcome re the tuning cap, over about 30% of the range at one end the plates foul & it shorts. I don't see any way to adjust plat e positioning, there's just a non-adjustable bearing at the front end and a nut at the back end. 'Polar' brand.

I also see that what I initially assumed were lytics are probably in many c ases paper caps. Looks like a lot of recapping will be needed. I don't like replacing original parts, but they probably won't work, aren't fixabale af aik, and are too small to be restuffed. And old paper caps are toxic.

NT

Reply to
tabbypurr

That's the British 'Wireless World' magazine, despite the URL.

Cheers

--
Syd
Reply to
Syd Rumpo

They may have originally been insulated by blocking the holes with putty or wax.

The voltage rating of the main smoothing capacitor should give you a clue. Alternatively, run it up on a variac and monitor the heater voltages.

Some American-made 110v sets were used in the UK on 240v with a 'line cord dropper' ( a resistive winding in the mains lead), but this one was clearly manufactured (not home-made) in the UK and looks about typical of the cheapest-of-the-cheap in the early 1950s.

--
~ Adrian Tuddenham ~ 
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Reply to
Adrian Tuddenham

You should use an isolation transformer when feeding the power to the radio. I'd use a Variac and then a 1:1 isolation transformer.

The construction was pretty common in the cheap radios in the 1950's. It was called 'universal power', as it could be used with DC feed, when the plug was put in in the correct polarity.

You should trace the heater/filament circuit to get a guess of the intended power line voltage.

The rectifier in pretty probably a selenium stack. It has a terrible stink when broken. The gas is poisonous, but the smell is stronger than the poison effect.

If it is broken, it can be replaced by a 1N4007.

--

-TV
Reply to
Tauno Voipio

Not physically possible when the grubscrew tops are flush. Replacing them with shorter ones I think is the way to go, and adding a class Y cap on the aerial wire. It's so much easier than trying to separate E&N.

That's what I looked at first, but it's just not accessible. I'd need to take it apart to see.

that's the plan. I'll go very slow with the hope of reforming the lytics.

Maybe. The cheap kit sets from the 40s & 50s I've seen were all black/brown cases. I like it anyway.

The glue is not water soluble. So it's going to have to be carefully chosen solvents - I gather PCTFE is vulnerable to a lot of solvents.

NT

Reply to
tabbypurr

fwiw universal sets used series valve heaters with a dropper. This has a filament transformer, so won't run on dc. I guess they didn't have high voltage low current heater valves available cheaply.

NT

Reply to
tabbypurr

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