1962 Murphy B485 7 transistor MW/LW portable - UK Vintage Radio Repair and Restoration Discussion Forum

howard · 31st Oct 2008, 11:49 pm

Hello again,

And another Murphy radio completed this week, this time an early transistor set. I restored one of these B485s early last year, a 1961 set with Ediswan transistors in a black/grey case with brass trim but this one marked 1962 inside is in a black/cream case with silver trim and has Mullard transistors including an OC81D + 2 x OC81s in the output stage and there's even an AF117 hidden inside it. Both the Murphy service sheet and the Trader sheet 1585 covering the maintenance of this model are available on the Vintage Radio Service Data website, via the link above. We used the Trader sheet.

I built it from two sets, the case came from one I've had for ages with worn printing which was working very quietly but only on one local MW station, and its chassis from a second set I won recently on eBay for £6 which I found to be working a little better, picking up plenty of stations but like the other one wouldn't play very loud. These sets were all supplied with an outer leather carry case as their plastic cases are rather flimsy but usually they survive well if kept in their carry cases, the only problem being that the carry cases tend to shrink and it can be a devil of a job getting the sets out of them, and if one isn't careful the top zip will badly scratch the plastic case (the second set had been badly scratched).

I dismantled both sets, collected together the better outer casework from one (the black top comes off easily after the two knobs and a screw either end underneath it are removed), and the better chassis from the other. I also removed the better square metal silver painted top plate from the scrap case by warming it up with a hairdryer and then by sliding a stanley knife blade underneath it to gently prise it off and likewise removed the worn one from the better case.

The knobs, push buttons and the outer panels were cleaned with upholstery cleaner with my toothbrush and all the loose rotten sponge inside the front panel brushed brushed away and the remaining sticky residue cleaned off of it, and from around the loudspeaker, with white spirit. I then cut and stuck new sponge strips under the front panel using Pritt Stick adhesive. The top black panel was polished with Brasso and the better metal plate stuck onto it. All the outer panels were then polished with Mer car polish and Mr.Sheen.

All the dust was cleaned off the chassis and as the ferrite rod aerial was broken I stuck it back together with Superglue, an invisible repair as the fracture was under one of the coils. The off switch, waveband switches and volume pot were all cleaned with Servisol 10 and the set reassembled and two 6 volt battery packs attached. It still didn't work well so I took it around to Ron Bryan to take a look at.

The quiescent current to each of the output transistors should be 1.5mA - those were checked and both were found to be slightly too high so were adjusted downwards, but that of course didn't improve the volume. So Ron worked his way back though the transistors in the set, checking all the voltages and they all seemed OK except for the bias to the OC81D driver transistor TR5 so the 2uf electrolytic coupling capacitor C52 was checked and found to be open circuit. That was replaced and away she went.

It works well this late Murphy B485, it picks up everything on MW and LW and sounds good too. I like the look of these unusual looking Murphys and this one is in superb condition now.

Howard

Darren-UK · 1st Nov 2008, 11:36 am

That looks a nice, tidy little chap Howard. Oddly, these turn up frequently complete with carrying case; unlike other radios that are often minus the case. Maybe this model came complete with case rather than the latter being an optional extra, I don't know.

There was also a very similar model (B385?). I once made one good'n by mixing parts from both models but I had to alter/shift the aerial socket IIRC to use the chassis from one and half the cabinet from another.

One problem I have found with these is difficulty getting the radio in and out of its carrying case, especially out. As a result there's a risk of scratching the radio with the brass zipper, so watch out for that.

howard · 1st Nov 2008, 4:43 pm

Quote:

Originally Posted by darren-uk

.......
There was also a very similar model (B385?). I once made one good'n by mixing parts from both models but I had to alter/shift the aerial socket IIRC to use the chassis from one and half the cabinet from another.

One problem I have found with these is difficulty getting the radio in and out of its carrying case, especially out. As a result there's a risk of scratching the radio with the brass zipper, so watch out for that.

Hello Darren,

The earlier version is the B385, the only obvious difference is the way that the two halves of the case are held together, the B485 has a spring clip and the B385 has a large screw (which is much better). Also the B485 cannot be used with the optional baffle cabinet.

I mentionned the tight fitting carrycase scratching problem above, but that can be avoided by rolling the zip webbing out over the outside of the leather case as shown below ....

Which reminds me, I now have enough bits to rebuild a B385

Howard

https://www.vintage-radio.net/forum/...1&d=1225554212

31st Oct 2008, 11:49 pm	#1
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	1962 Murphy B485 7 transistor MW/LW portable Hello again, And another Murphy radio completed this week, this time an early transistor set. I restored one of these B485s early last year, a 1961 set with Ediswan transistors in a black/grey case with brass trim but this one marked 1962 inside is in a black/cream case with silver trim and has Mullard transistors including an OC81D + 2 x OC81s in the output stage and there's even an AF117 hidden inside it. Both the Murphy service sheet and the Trader sheet 1585 covering the maintenance of this model are available on the Vintage Radio Service Data website, via the link above. We used the Trader sheet. I built it from two sets, the case came from one I've had for ages with worn printing which was working very quietly but only on one local MW station, and its chassis from a second set I won recently on eBay for £6 which I found to be working a little better, picking up plenty of stations but like the other one wouldn't play very loud. These sets were all supplied with an outer leather carry case as their plastic cases are rather flimsy but usually they survive well if kept in their carry cases, the only problem being that the carry cases tend to shrink and it can be a devil of a job getting the sets out of them, and if one isn't careful the top zip will badly scratch the plastic case (the second set had been badly scratched). I dismantled both sets, collected together the better outer casework from one (the black top comes off easily after the two knobs and a screw either end underneath it are removed), and the better chassis from the other. I also removed the better square metal silver painted top plate from the scrap case by warming it up with a hairdryer and then by sliding a stanley knife blade underneath it to gently prise it off and likewise removed the worn one from the better case. The knobs, push buttons and the outer panels were cleaned with upholstery cleaner with my toothbrush and all the loose rotten sponge inside the front panel brushed brushed away and the remaining sticky residue cleaned off of it, and from around the loudspeaker, with white spirit. I then cut and stuck new sponge strips under the front panel using Pritt Stick adhesive. The top black panel was polished with Brasso and the better metal plate stuck onto it. All the outer panels were then polished with Mer car polish and Mr.Sheen. All the dust was cleaned off the chassis and as the ferrite rod aerial was broken I stuck it back together with Superglue, an invisible repair as the fracture was under one of the coils. The off switch, waveband switches and volume pot were all cleaned with Servisol 10 and the set reassembled and two 6 volt battery packs attached. It still didn't work well so I took it around to Ron Bryan to take a look at. The quiescent current to each of the output transistors should be 1.5mA - those were checked and both were found to be slightly too high so were adjusted downwards, but that of course didn't improve the volume. So Ron worked his way back though the transistors in the set, checking all the voltages and they all seemed OK except for the bias to the OC81D driver transistor TR5 so the 2uf electrolytic coupling capacitor C52 was checked and found to be open circuit. That was replaced and away she went. It works well this late Murphy B485, it picks up everything on MW and LW and sounds good too. I like the look of these unusual looking Murphys and this one is in superb condition now. Howard Attached Thumbnails Last edited by howard; 1st Nov 2008 at 12:09 am.

1st Nov 2008, 11:36 am	#2
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: 1962 Murphy B485 7 transistor MW/LW portable That looks a nice, tidy little chap Howard. Oddly, these turn up frequently complete with carrying case; unlike other radios that are often minus the case. Maybe this model came complete with case rather than the latter being an optional extra, I don't know. There was also a very similar model (B385?). I once made one good'n by mixing parts from both models but I had to alter/shift the aerial socket IIRC to use the chassis from one and half the cabinet from another. One problem I have found with these is difficulty getting the radio in and out of its carrying case, especially out. As a result there's a risk of scratching the radio with the brass zipper, so watch out for that.