Richmond Radio AA510.

[FERNSEH]

Found at a car meet up yesterday in Bedale North Yorkshire this unusual radio set made by a firm called Richmond, the model is AA510. There is some limited information about the set on the Radiomuseum website.
Some details about the set. Three wavebands L.M.S. Valve lineup is: X61M, W61, DH63, KT61 and an U50 as the HT rectifier. Acquired the set for £4.
Worth noting the town of Richmond is only ten miles from Bedale where the set was found. Was the set made in Richmond?
The third picture shows that there is some unpleasantness inside the cabinet.

DFWB.

[ms660]

I wonder if it was a dept. store/chain store job.

Lissen were in Richmond, Surrey.

Just an idea into the mix.

Lawrence.

[Nickthedentist]

The cabinet certainly has a very Defiant/Plessey look about it.

[FERNSEH]

Hi Nick.
I'm sure I've seen those control knobs on other sets. In fact the set was bought by a friend simply for those knobs.
There's evidence of wee creatures having made their home inside the cabinet and made a meal of the loudspeaker cone.
Worth restoration or is the set destined for the bin?

DFWB.

[Nickthedentist]

Yes, they're very characteristic, but I can't think of any other set that definitely uses them off the top of my head.

The chassis looks very rusty in places. Are the output and mains transformer OK? If yes, then it might well be worth a quick and dirty restoration as it seems to be a rare set.

N.

[FERNSEH]

Hi Nick,
Without removing the chassis from the cabinet it's not possible to make accurate resistance readings of the output transformer. However, there is a resistance reading of 1,200 ohms between the anode of the KT61 and the filament of the U50 HT rectifier. The loudspeaker is of the energised type.
The chassis will have to be removed to check the primary of the mains transformer.

DFWB.

[FERNSEH]

This evening the chassis and loudspeaker were removed from the cabinet. Before anything is done to the set a replacement loudspeaker will have to be found.
The wee creatures have certainly made a meal of the 'speaker cone.

DFWB.

[FERNSEH]

Picture of the underside of the chassis. As long as the coil pack assembly is serviceable it should be an easy task to return this set to working order.
The 47ohm resistor in the negative HT return is likely to supply the AVC delay voltage.
The mains lead is anchored on the HT rectifier valveholder. Not very nice so the replacement lead will be rerouted direct to the switch.

DFWB.

[FERNSEH]

A good PM magnet loudspeaker has been found and fitted to replace the original energised unit.

DFWB.

[Brigham]

Doesn't that affect the HT smoothing?

[FERNSEH]

A smoothing choke will be fitted on the chassis. I recently modified an MRG radiogram in a similar manner.

https://vintage-radio.net/forum/showthread.php?t=137667

See post #19.

DFWB.

[FERNSEH]

A smoothing choke was fitted yesterday. It occupies the position of one of the HT smoothing capacitors. The original two 16mfd elcos were useless and have been replaced by a single 16 + 16mfd capacitor.
The 47ohm resistor in the HT negative return has been retained and the 0.5mfd capacitor across it replaced by a 200mfd electrolytic capacitor. The negative voltage developed across this resistor provides the AVC delay potential.

DFWB.

[Nickthedentist]

I admire your perseverance, David, well done.

It will be very rewarding when it's finished and working, and possibly unique.

[FERNSEH]

Hi Nick,
the set actually works - in a fashion. Tested the set last night without the rectifier valve. Heaters glowing, 350 - 0 - 350 on the HT winding tags.
Today connected the set to the variac, plugged in a 5Y3GC rectifier valve.
By the time the HT supply is 100volts a hum could heard in the loudspeaker when the top cap of the 6Q7G DDT was touched.
Full mains supplied and it's receiving medium wave stations, plenty sound but with bad distortion.
The future's good for this set.

DFWB.

[Heatercathodeshort]

Another slag heap special David? The knobs have an Argosy/Ace type appearance. Probably a Plessey as suggested. You see them everywhere.
I don't think the famous sausage company ever produced a radio. John.

[FERNSEH]

Hi John,
it sure looks horrible but in due course it will be returned to pristine condition. In fact it's now working well on the medium and short wavebands, hopeless on LW. Ripple on HT rail is 1volt P - P. No distortion now.

DFWB.

[Ed_Dinning]

Hi John, this Richmond is a refined county town, no sign of slag heaps within 40 miles. The locals would be surprised there was even manufacturing in the area.

Ed