1948 Murphy A124 3 valve + rectifier SW/MW/LW baffle receiver - UK Vintage Radio Repair and Restoration Discussion Forum

howard · 5th May 2008, 2:30 pm

Hello again,

Now here's an interesting old radio, indeed there's one of these in the Science Museum. It's case is the sort of design that one either loves or hates cos it certainly is different. I like it but others who have seen it feel differently. It is built from three slabs of veneered plywood with an 8" loudspeaker fitted in the middle of its flat "baffle board" mahogany front panel with a lit perspex dial above it suspended half an inch from the surface. It has four controls along the bottom, for tone (3 positions), off/on/volume, waveband selection (SW/MW/LW) and tuning. Murphy built several sets in this baffle design in the 1940s and 1950s, and my parents bought an A104 new in 1949, which was handed down to me a few years later when I was 6 years old, my very first radio, and I had it in my room for many years, so I've had a soft spot for these Murphy radios ever since. I won this one at the last Harpenden auction for £20, described as in full working order. It was far from perfect and complete though, it had a few light scratches, there were a couple of small pieces of veneer missing from both leading edges of the side panels, part of one of the light fittings had been replaced with a tatty piece of bent metal and the original loudspeaker cover had been replaced with some horrible modern black loudspeaker material, but considering it was 60 years old, it was overall in pretty good cosmetic condition. When I got it home I took a look inside (removal of the back cover enables easy access to the entire chassis) and was dismayed to find that it had been partly rewired with old lighting flex, its two light fittings had been secured with cable ties and its bulb holders wrapped in some sort of clear shrink sleeving. I plugged it in and fitted a long aerial wire (this set has no built in aerial), and it barely worked, it was very quiet and picked up very little but then I found that it still had all but one of its original wax capacitors in it. It had lost its original U404 rectifier valve and in its place was a UY85 with its valve base fitted under the chassis, a perfectly acceptable replacement I understand. Most of its original wiring was still present and some was in poor condition but its grey painted steel chassis was corrosion free. It's original smoothing capacitors are both dated 1948. Service data for this set, Trader service sheet 933 dated 26th November 1949, is available from Paul Stenning's website above or just its circuit diagram from here ...

http://www.******************************/A124.jpg

As it was incomplete I looked out for another scrap set for parts and I acquired one for £5, delivered. This sadly was a write-off with a damaged case and rusty chassis but it had an undamaged cloth cover over its loudspeaker, some light fittings and a U404 valve base. I removed the cloth, cleaned it up with upholstery cleaner, and fitted it to my set and that did improve its appearance. I then cleaned the case and polished the mahogany baffle board with Topps dark wood polish which did a brilliant job disguising the scratches. As veneer was conveniently peeling off the scrap set, I cut off a couple of 1 inch pieces and stuck them onto the leading edges of the side panels with wood glue, gently sanded down the edges and varnished them. They match well so this repair is virtually indetectable. The scrap set had an excellent perspex dial inside which I offered on the forum, Leon Crampin who lives locally came and collected it for his Murphy U124, an AC/DC version of the set. He had a listen to my set and he agreed that it was not working at all well, but was impressed by its cosmetic condition.

I set about restoring the chassis and replaced all but two of its Hunts wax capacitors (7 x 0.05uf, 1 x 0.002uf) with new North American metallized polyester film tubular axials of the exact capacitances, one corroded 1000 volt US made Sprague 0.01uf capacitor with a high voltage LCR and all the lighting flex and the worst of the rotten wiring using new RS silicone wire. I tested the old caps and only one wax cap wasn't leaky, two were open circuit but the Sprague cap was fine. I acquired three valves, second hand but 100% 10C1 and 10F9, and a brand new U404 for £7 and fitted the first two (the original 10F9 was absolutely knackered) and the set started to work well with plenty of volume, and I have to say, sounding very good ! I collected together two complete light fittings, polished them and securely fitted them using two large circlips on each and rewrapped the bulb holders in two layers of large black shrink sleeving which I found in B&Q. I replaced the bulbs as the ones fitted were wrong (should be 6.2 volt 0.3 amp) and then I took the set over to Ron Bryan for testing and to have the remaining awkwardly situated capacitors replaced. The caps were replaced (both were leaky) and the HT voltages then checked and all was well and its two smoothing caps were fine and weren't getting warm. Ron also tweaked the MW trimmer a fraction as the set wasn't quite picking up County Sound radio on 192 metres MW.

I replaced the rest of the rotten wiring (and most of it was rotten !) and reinstated the U404 rectifier valve. The set was now working well on all 3 wavebands, especially SW where it was picking up loads of stations. It did hum though on station on MW where I was working on it in the kitchen, but moving it into the living room reduced that significantly. It didn't do this at Ron's and we reckon this problem which I occasionally have with older radios is caused by the proximity of the powerful 192m MW County Sound transmitter which is only a few hundred yards away.

The set then went back to Ron Bryan for re-alignment. It was felt that LW was a little less sensitive than MW so Ron checked one or two of the mica caps in the circuit and found one that was out of tolerance so that was replaced. And then Leon brought his U124 around for comparison and there was very little to choose between them despite the U124 having an extra stage. Interestingly, his set also hummed in the kitchen ....

This is a classic post-war 1940s British radio now in full working order and in excellent cosmetic condition. It is a 3 valve short superhet with no internal aerial so it does need a long external aerial (and it should be earthed too) and it then manages to pick up just about everything on all three AM wavebands loud and clear. This old set sounds so exceptionally good that one forgets its odd looks when listening to it .........

Howard

Leon Crampin · 5th May 2008, 3:20 pm

Having seen Howard's set I can confirm that he has made an excellent job of restoring it. It puts my U124 to shame, although I am not responsible for some of the bodges within it.

My U124 was seriously disfigured by having a warped and faded scale plate and two incorrect knobs. This has all been restored thanks to the spare bits from Howard's scrap set (Thanks, Howard). I can confirm that these sets do seem to work rather better than their "paper" specification might suggest. Certainly, the use of a baffle rather than a box avoids cabinet resonances and the sets are not lacking in bass response.

Now I just have to get my U124 to look as smart as Howard's A124...

Leon.

howard · 5th May 2008, 4:31 pm

Quote:

Originally Posted by Leon Crampin

.............Now I just have to get my U124 to look as smart as Howard's A124... Leon.

Hello Leon,

I thought your U124 looked nice actually. It's old scale really was knackered though !

Here are pics of the chassis before worked started, the restored and re-restored lamps and wiring, and the old capacitors,

Howard

paulsherwin · 5th May 2008, 5:16 pm

Quote:

Originally Posted by Leon Crampin

I can confirm that these sets do seem to work rather better than their "paper" specification might suggest. Certainly, the use of a baffle rather than a box avoids cabinet resonances and the sets are not lacking in bass response.

Short superhets like this were favoured by several big makers in the 40s and early 50s, especially Pye. They do work very well with a big longwire aerial (which many people would have had anyway when the sets were new) but they can struggle a bit on the weaker stations with a frame aerial or the traditional length of wire draped along the skirting board.

Paul

howard · 8th May 2008, 1:56 pm

Hello again,

We found one more bodge which needed fixing on the Murphy - the tone switch although working seemed slack and didn't park firmly in each of its three positions. Unfortunately the tone switch in the scrap set was broken so we couldn't use that, but comparing it with the other it had had a replacement ball bearing fitted which was twice the size of the original and instead of been fitted under two retaining springs had been fitted between them.

As the damaged switch had a good spindle and original ball bearing, Ron took the spindles out of both switches by removing their small retaining clips and swapped them over. The restored tone switch works perfectly now.

Pics below of the bodged spindle after removal, the damaged switch and the repaired switch back in the Murphy.

This Murphy A124 sounds so good on MW I use it all the time for listening to County Sound radio.

Howard

5th May 2008, 2:30 pm	#1
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	1948 Murphy A124 3 valve + rectifier SW/MW/LW baffle receiver Hello again, Now here's an interesting old radio, indeed there's one of these in the Science Museum. It's case is the sort of design that one either loves or hates cos it certainly is different. I like it but others who have seen it feel differently. It is built from three slabs of veneered plywood with an 8" loudspeaker fitted in the middle of its flat "baffle board" mahogany front panel with a lit perspex dial above it suspended half an inch from the surface. It has four controls along the bottom, for tone (3 positions), off/on/volume, waveband selection (SW/MW/LW) and tuning. Murphy built several sets in this baffle design in the 1940s and 1950s, and my parents bought an A104 new in 1949, which was handed down to me a few years later when I was 6 years old, my very first radio, and I had it in my room for many years, so I've had a soft spot for these Murphy radios ever since. I won this one at the last Harpenden auction for £20, described as in full working order. It was far from perfect and complete though, it had a few light scratches, there were a couple of small pieces of veneer missing from both leading edges of the side panels, part of one of the light fittings had been replaced with a tatty piece of bent metal and the original loudspeaker cover had been replaced with some horrible modern black loudspeaker material, but considering it was 60 years old, it was overall in pretty good cosmetic condition. When I got it home I took a look inside (removal of the back cover enables easy access to the entire chassis) and was dismayed to find that it had been partly rewired with old lighting flex, its two light fittings had been secured with cable ties and its bulb holders wrapped in some sort of clear shrink sleeving. I plugged it in and fitted a long aerial wire (this set has no built in aerial), and it barely worked, it was very quiet and picked up very little but then I found that it still had all but one of its original wax capacitors in it. It had lost its original U404 rectifier valve and in its place was a UY85 with its valve base fitted under the chassis, a perfectly acceptable replacement I understand. Most of its original wiring was still present and some was in poor condition but its grey painted steel chassis was corrosion free. It's original smoothing capacitors are both dated 1948. Service data for this set, Trader service sheet 933 dated 26th November 1949, is available from Paul Stenning's website above or just its circuit diagram from here ... http://www.******************************/A124.jpg As it was incomplete I looked out for another scrap set for parts and I acquired one for £5, delivered. This sadly was a write-off with a damaged case and rusty chassis but it had an undamaged cloth cover over its loudspeaker, some light fittings and a U404 valve base. I removed the cloth, cleaned it up with upholstery cleaner, and fitted it to my set and that did improve its appearance. I then cleaned the case and polished the mahogany baffle board with Topps dark wood polish which did a brilliant job disguising the scratches. As veneer was conveniently peeling off the scrap set, I cut off a couple of 1 inch pieces and stuck them onto the leading edges of the side panels with wood glue, gently sanded down the edges and varnished them. They match well so this repair is virtually indetectable. The scrap set had an excellent perspex dial inside which I offered on the forum, Leon Crampin who lives locally came and collected it for his Murphy U124, an AC/DC version of the set. He had a listen to my set and he agreed that it was not working at all well, but was impressed by its cosmetic condition. I set about restoring the chassis and replaced all but two of its Hunts wax capacitors (7 x 0.05uf, 1 x 0.002uf) with new North American metallized polyester film tubular axials of the exact capacitances, one corroded 1000 volt US made Sprague 0.01uf capacitor with a high voltage LCR and all the lighting flex and the worst of the rotten wiring using new RS silicone wire. I tested the old caps and only one wax cap wasn't leaky, two were open circuit but the Sprague cap was fine. I acquired three valves, second hand but 100% 10C1 and 10F9, and a brand new U404 for £7 and fitted the first two (the original 10F9 was absolutely knackered) and the set started to work well with plenty of volume, and I have to say, sounding very good ! I collected together two complete light fittings, polished them and securely fitted them using two large circlips on each and rewrapped the bulb holders in two layers of large black shrink sleeving which I found in B&Q. I replaced the bulbs as the ones fitted were wrong (should be 6.2 volt 0.3 amp) and then I took the set over to Ron Bryan for testing and to have the remaining awkwardly situated capacitors replaced. The caps were replaced (both were leaky) and the HT voltages then checked and all was well and its two smoothing caps were fine and weren't getting warm. Ron also tweaked the MW trimmer a fraction as the set wasn't quite picking up County Sound radio on 192 metres MW. I replaced the rest of the rotten wiring (and most of it was rotten !) and reinstated the U404 rectifier valve. The set was now working well on all 3 wavebands, especially SW where it was picking up loads of stations. It did hum though on station on MW where I was working on it in the kitchen, but moving it into the living room reduced that significantly. It didn't do this at Ron's and we reckon this problem which I occasionally have with older radios is caused by the proximity of the powerful 192m MW County Sound transmitter which is only a few hundred yards away. The set then went back to Ron Bryan for re-alignment. It was felt that LW was a little less sensitive than MW so Ron checked one or two of the mica caps in the circuit and found one that was out of tolerance so that was replaced. And then Leon brought his U124 around for comparison and there was very little to choose between them despite the U124 having an extra stage. Interestingly, his set also hummed in the kitchen .... This is a classic post-war 1940s British radio now in full working order and in excellent cosmetic condition. It is a 3 valve short superhet with no internal aerial so it does need a long external aerial (and it should be earthed too) and it then manages to pick up just about everything on all three AM wavebands loud and clear. This old set sounds so exceptionally good that one forgets its odd looks when listening to it ......... Howard Attached Thumbnails

5th May 2008, 3:20 pm	#2
Leon Crampin Octode Join Date: Nov 2005 Location: Surrey, UK. Posts: 1,870	Re: 1948 Murphy A124 3 valve + rectifier SW/MW/LW baffle receiver Having seen Howard's set I can confirm that he has made an excellent job of restoring it. It puts my U124 to shame, although I am not responsible for some of the bodges within it. My U124 was seriously disfigured by having a warped and faded scale plate and two incorrect knobs. This has all been restored thanks to the spare bits from Howard's scrap set (Thanks, Howard). I can confirm that these sets do seem to work rather better than their "paper" specification might suggest. Certainly, the use of a baffle rather than a box avoids cabinet resonances and the sets are not lacking in bass response. Now I just have to get my U124 to look as smart as Howard's A124... Leon.

8th May 2008, 1:56 pm	#5
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	Re: 1948 Murphy A124 3 valve + rectifier SW/MW/LW baffle receiver Hello again, We found one more bodge which needed fixing on the Murphy - the tone switch although working seemed slack and didn't park firmly in each of its three positions. Unfortunately the tone switch in the scrap set was broken so we couldn't use that, but comparing it with the other it had had a replacement ball bearing fitted which was twice the size of the original and instead of been fitted under two retaining springs had been fitted between them. As the damaged switch had a good spindle and original ball bearing, Ron took the spindles out of both switches by removing their small retaining clips and swapped them over. The restored tone switch works perfectly now. Pics below of the bodged spindle after removal, the damaged switch and the repaired switch back in the Murphy. This Murphy A124 sounds so good on MW I use it all the time for listening to County Sound radio. Howard Attached Thumbnails Last edited by howard; 8th May 2008 at 2:01 pm.