RGD A112. Help please!

[christerrygwyns]

Hi boys and girls, I bought an RGD model A112 about 18 years back in a junk shop (it was love at first sight). She had been working ok, but a move to a very much smaller abode necessitated a four year holiday for her in Mum's (dry) loft. She is now out of the loft, but has a broken valve. The markings on the valve are not readable. How can I Iidentify the dead valve? I have spoken to a vintage component supplier who says he can't find an RGD A112 in his catalogues. Does anyone know who bought RGD in the 50's? Perhaps it is in the catalogue under that name? Does anyone have an A112, could look in the back and let me know what the markings on my dead valve are? Thanks, Chris.

[Andrewausfa]

I think it's a 1-12 which would be when R.G.D. were under the Regentone umbrella.

You omitted to mention where the dead valve actually is on the chassis so have a look at the valve numbers on the chassis, you should have one of EL84, EF85, EZ80, EABC80, ECC85, EABC80. There should be a magic eye valve visible from the front of the set (I've no idea what your set looks like) which should be an EM80.

If there's none of these valves then it's not the set I thought it was

Andrew

[christerrygwyns]

I think it's a 1-12 which would be when R.G.D. were under the Regentone umbrella.

You omitted to mention where the dead valve actually is on the chassis so have a look at the valve numbers on the chassis, you should have one of EL84, EF85, EZ80, EABC80, ECC85, EABC80. There should be a magic eye valve visible from the front of the set (I've no idea what your set looks like) which should be an EM80.

If there's none of these valves then it's not the set I thought it was

Andrew

Thanks Andrew. I'll clean the chassis and have a look. As you stand in front of the back of the radio it is the valve to the far left. It does indeed have a magic eye. :-)

[Joe]

Sounds like the EF85 then.

If they are Mullard (or another Philips brand) valves they have another set of numbers etched on which can be deciphered, though it ain't easy!

- Joe

[Yorkie]

If the model is indeed a '1-2', as seems to be the case, the valves are:

V1 ECC85 (VHF Tuner)
V2 ECH81
V3 EF85
V4 EABC80
V5 EL84
V6 EZ80
V7 EM80 (Msgic Eye).

The location of the valves, looking on top of the chassis from the rear, are:

Vaves nearest to the rear apron of the chassis:

Valve next to the mains transformer/voltage selector is V6.
Valve between the two square IF transfomers is V3.
Valve to the far right next to the external loudspeaker socket/pick up is V5

The innermost valves are (left to right):

V2 - behind V6, near to the mains transformer.
V4 - just right of centre.

(You'll most likely find any of these commonplace valves on e-bay)

If you intend to put the radio into regular use I'd suggest that the least work you should do on it would be to replace C57 (0.05uF - use modern equivalent 0.047uF) which couples the anode of V4 to the grid of V5. This is known by the hackneyed term 'that capacitor' and they are often leaky in the electrical sense. Its role in life is to allow AF signals to pass from the anode of the IF stage to the grid of the AF amplifier while blocking DC voltage. If it fails to do that effectively it can cause excess current to be drawn, overdrive the audio valve, stress the output transformer and cause other undesireable problems. (C57 is located under the chassis on a tagstrip next to the output transformer). Most restorers change this capacitor on any valve radio as a matter of course. Personally, I also change the cathode bypass capacitor, which isn't so critical. It's C60 in your set - 25uF 12V. A modern equivalent would be 22uF 25V, (which will look comically small alongside the original, as do many modern components, such as resistors).

Obviously you need the service data (which runs to 6 pages) before you start poking around.

Sorry if I'm telling you stuff you already know.

Hope that helps a bit Chris.

Best of luck with the set - Long Wave, Medium Wave, Short Wave and VHF. What's not to like about that?

[christerrygwyns]

Many thanks for your help, especially to David. The valve is an EZ80, David's post suggested this, and what remains of the markings on the valve confirm it. I'll get pushing buttons on Ebay soon. I have found a firm near Guildford who are going to take my radio in for a service, and won't charge the vast fortunes quoted elsewhere. I couldn't tell a c57 capacitor from a heat sink, although I do possess a soldering iron (somewhere) and could swap components with someone over my shoulder pointing out what to do, I really don't know what I'm doing. One thing surprises me about my little old wireless is that there is nothing about it on the interweb. Not on the RGD museum website, nor on a Regentone products list. Not on any vintage radio site I have come across. Is she so rare a beast that she is virtually unknown, or so common as to be unworthy of note. I have taken a photo of her internal workings and will post them on this forum (when I have worked out how to) for those who may be interested to see.

[tiv48]

when looking for your ez80 please note that it does not have to be mullard or philips they tend to be expensive.
try to get a new old stock one they lead a hard life.
if c57 has not been replaced you may find you will need an el84.
rob t

[Yorkie]

The EZ80 is the rectifier valve. It's job is to convert the AC mains to DC to suppy the HT to the other valves. As Rob says, if you don't get C57 changed, it may soon see off the EL84 output valve, and risks other potential problems. (A new capacitor would cost no more than a pound, plus fitting). It's a very practical set for everyday use in that it has the FM band, and doesn't need an aerial for LW and MW as it has an internal ferrite rod aerial. It only needs an external aerial for the short-wave band, which could be no more than say 10 - 15 ft of wire laying on the floor.

RGD didn't skimp on the design. It doesn't use cost-cutting techniques such as a live chassis AC/DC techniques and mains dropper - it is an AC only design and uses a mains transformer. It also has a high component count, running to 65 resistors and 43 capacitors. For comparison, the commonplace Bush DAC90A - a basic AC/D LW/MW only set from 1948 often used by rental companies, and much favoured today by some (as much as anything because it is commonplace and basic, as well as Bakelite) - has just 22 capacitors and 17 resistors. It's unlikely that the first owner of your RG 1-12 would have been able to pay for it outright, but on easy terms.

Although it would have been an expensive radio in its day, the sad fact is that it will most likely be worth less now than the sum total of the valves, but then most of us on here aren't interested in the cash value of old radios - we enjoy them because they're old, they're radios, and they use valves. There are lots of people around today who know the price of everything and the value of nothing. Many old radios are rare or at least uncommon, but that doesn't always mean that they're sought after or valuable. They may have been made in low numbers because they lacked appeal, and the passage of time may not necessarily make them any more appealing now than when they were new. I'm not directing those remarks at this radio - just generalising.

Incidentaly, if the magic eye is past its best or very dim, it's only for appearance - it has no bearing on the function of the set - your listen to a radio with your ears - not your eyes and your ears will tell you if the set is correctly tuned to a station! Magic eyes were little more than a sales gimmick, soon wore out, and are expensive.

Even though you don't wish to delve inside the radio yourself, you might nevertheless like to download a copy of the 6-page data for it, which will only set you back £1.99 from this link Chris:

http://www.service-data.com/section.php/7176/1

Just on final point - make sure that the voltage selector on the rear of the set is set to the higher setting - 230-250V, which will be kinder to the set and won't degrade its performance.


Hope that's of interest.