RGD516 Receiver from 1937

The design is not to everyone's taste perhaps and the set is very heavy and useful for standing things on its top. The loudspeaker is mounted at an angle which is a little odd. Perhaps the designers made a mistake with their measurements and needed to fit the speaker in place this way because it wouldn't fit flat against the front panel. However the shape of the receiver makes it ideal to place in the right corner of a room so the speaker is facing into the main area. The condition of the woodwork is a bit scruffy in this light so will need a really good clean and polish.

 

The set uses old B7 based valves and the rectifier on the right looks a bit odd sitting on an aluminium base. At first sight the original has been substituted for a more common type with a different base... I'll check later.

The original valves are as follows:- RF Amplifier=Mullard VP4B, Frequency Changer=Mazda AC/TH1, IF Amplifier Mullard VP4B, Audio Output, which includes the Detector and AVC diodes=Mazda AC/2PenDD and not forgetting the Magic Eye=Mullard TV4 and Full-Wave Rectifier=UU4. The choice would seem to be selected by virtue of the quality/performance and perhaps cost as most makers choose the same mmanufacturer for all their valves.?

 

You can see below that the rectifier is not the original type. 

 

 The loudspeaker is the usual mains energised type. It was detached before the set was posted to me to prevent possible damage.

 

 The labels on the rear cover. The most annoying thing with some acquisitions is a missing rear cover with absence on the chassis of the makers information sometimes making a set completely anonymous. Below these is the label fixed to the case showing that Mr Marconi's stealth tax had been paid together with evidence that cash had also been paid to EMI, Hazelpat and STC.

 

 

 

 

 From the label found inside the radio, it appears the loudspeaker was repaired back in 1949.
   

 The dial, carrying Long, Medium and Short Wave stations looks a little obscure (other than the white lettering) because it relies on illumination from its pilot lamps. You can see the magic eye at the top. Nowadays most magic eyes will be short of emission and of little use.

 

 The chassis... front and rear views.

 

 

 Below, a view of the tuning coils visible once the three aluminium screening cans have been unscrewed and detached.
 
 Under the chassis a new volume control and a couple of smoothing condensers have been fitted, I should say in the 1960s...

 Once the chassis had been removed from the case it was apparent that something was preventing the wavechange knob rotating. The control consists of a set of yaxley-style wafers carrying a flat strip through them, At the front of the chassis was a metal assembly with an ident for 4 positions (Long/Medium/Short & Gram) and this was completely bent out of shape so the 1/4 inch spindle through its centre couldn't turn. To fix this was difficult. First the metal assembly was detached from the front panel, then a lever bolted to the flat strip through the wafers had to be slackened before the thing could be withdrawn through the hole in the front of the chassis. As luck would have it the lever was jammed because one of two securing grub screws was underneath. I pulled the flat strip and it almost came out but then the solder holding the strip to the ident assembly failed. I was then able to slacken the second grub screw and remove everything. I managed to flatten the metalwork and restore the ident assembly to working order, then resolder the flat strip and thread it through the wafers. The wavechange switch then worked normally.

 
 This lever operates an indicator, visible through the hole below the magic eye, showing the selected waveband.
   

I powered the set and found a number of condensers had failed so decided to shelve the exercise for the time being but to partly restore the cabinet. I found that isopropyl alcohol produced an acceptable finish as long as it wasn't allowed to remain in one place for more than a second or two. It removed deposits of grime and reflowed the surface polish thus covering blemishes. Not perfect but a lot better than it was.

 

See the Trader Sheet

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