Murphy A242

[Count Moriarty]

A rather imposing early FM receiver from 1955. This one was presented to me gratis by a friend and considering where it started, I'm quite pleased with the way it's turned out. It had been roughed up during its life and evidently once belonged to the 'last of the smoking Seagoons', but I reckoned there was a good radio trying to get out. Probably a rather dull project with no particular challenges, but I did rather enjoy it nonetheless.

Whipped the chassis out and replaced the mains lead, about half of which was sans fabric covering. 'That' capacitor was changed also, and with the knowledge that the set had been tried before arrival with no ill effects, I took the plunge with the mains.

At least it was alive. Short wave: insensitive. Medium wave: insensitive to halfway up the band, then dead. Long wave: dead. FM: yes, that was dead too.

The AM problems all stemmed from the same cause: leaky capacitors around the frequency changer. When these had been replaced, it worked well on all three AM bands.

The tone control caused a loud 'crack' when moved to position 4 (the most muffled) and the sound would all but disappear. Capacitors in the tone control circuit were the cause here; there was lots of DC on the rotary switch so C77 (Murphy data) was changed.

The FM problem was traced down to the EC92 being low emission - a replacement kindly donated by a forum member restored FM.

The speaker 'cloth' didn't prove troublesome to clean; it seems to be Tygan and scrubbed up well with soap and water. The cabinet was cut back to a shine with Rustins Finish Reviver and the scratches dealt with using Rustins Scratch Remover - there are still one or two visible, but it's much better and overall it's presentable.

The 6M2 tuning eye is very low emission, but it is visible and it will 'keep' until another one can be found.

[Aerodyne]

Nice work, Jim. I've got a rather similar Murphy (need to check on the model number) which some joker has kindly painted, including the grille material. Silver, would you believe. Maybe that's the next for the bench!
-Tony

[Jonster]

Good job that, well done! I had one of these many years ago as a youngster and could never get it to work properly, there are quite a few about though and I think one day I will have another, I quite like the styling of them for some reason!

[Count Moriarty]

They're certainly not as bonkers as some of the Murphy designs - with the possible exception of Tony's silver one - always found metallic paints the very devil to remove from plastic so I wish him the best of luck! I think they're a little under-appreciated, but this one acquits itself very well.

[TuningIndicator]

I LOVE these radios.
When working properly (I'm listening to mine now), the performance is **superb**.
It's well worth changing V4 to an EF89 (as per the Murphy manual), this will greatly improve performance.
VHF performance centres on V1 and V2 being up to scratch.

[chipp1968]

I have The model with oval magic eye window. Mine belonged to my grandparents .I had it professionally ...restored some years ago,at great expense after which it didnt work on FM , so it went back , supposedly a valve . A year or two later after my Dad died which prompted me to get it back ,but was so disheartened that the dial was scratched and two of the knobs were ruff ones from another set, and the Maj eye didn't seam to work,so I put it up in the roof
I really should get it down again. I used it as a teenager in my bedroom in the 80s and remember it was very vibrant sounding .I remember picking up a neighbour talking on CB radio and the Police on it.It didn't interest me much in those days as it was much too modern.

[Steve_P]

Lovely sets these. Murphy's either are or aren't. I bet it does acquit itself well.

The Magic Eye problem is common. Try upping the anode voltage.

Cheers,

Steve P.

[JimMac53]

Nice job! I've done two of these, an early set without the mods, and a later set with the mods. Later models moved the VHF oscillator to below the FM band. They are great sets to work on as the chassis can be put into almost any position. The Murphy Service Manual is a great help. (It has a great section on how a ratio detector works -- good reading for any FM radio.) Beware of C8, which is a Hunts bomb in the VHF tuner. It is difficult to change and is critical to proper VHF performance.

The cabinet is a lovely French walnut veneer. My cabinets were in such poor condition that I stripped the finish back to bare wood and then refinished with Danish oil. Good luck in finding a 6M2. I've not been successful. You can use an EM34 (without wiring changes), but they are expensive too. You might want to consider a Russian 6E5C, which are plentiful and cheap, but it will require wiring changes. However, you could build a jumper cable that leaves the Murphy wiring alone, and mates to the 6E5C (this is what I've done). That way, if a 6M2 ever comes available, I can switch back to it by unplugging the jumper cable from the 6M2 socket and installing the 6M2.

[TuningIndicator]

I've done three (so ner!) just kidding!
My most recent was the most challenging, I ended up changing all of the Hunts (naturally), plus all resistors over 100R. Some had almost doubled in value.
The OPTXs are susceptible to failing just for fun.
VHF tuning is pin-sharp, with no drift.
Murphy engineers were absolutely at the top of their game with this set (given available valves at the time)

[JimMac53]

I certainly agree concerning the output Tx, but that has to do with the current the 6P1 output valve can draw particularly when THAT capacitor goes leaky. One of mine was gone and upon the recommendation I got on this forum, I replaced it with the generic one from either RS or Farnell. I added an extra filter section to make up for the loss of the hum bucking feature of the original Tx. It sounds fine (at least to my tin ears) -- at least there is no hum.

Concerning Murphy engineers being at the top of there game, I have to respectfully disagree. They were hamstrung by being obligated to use Mazda valves which excluded the valves everyone else was using, so you ended up with the 9 pin 6C9 (not to be confused with the 10 pin 6C9, which I bought because I didn't know). Murphy significantly changed the design during the production run -- changing valves, moving the VHF oscillator from above to below, AGC changes, etc, and then, didn't stay with that design for the A252 (or A262). Clearly they had production problems. The VHF gain from one s/n to the next can vary significantly (due to just C8).

It's a nice radio with a great look (iconic to my mind) and has a wonderful sound (the 6P1 is a powerful tube), expensive in it's time -- the beginning of Hifi. It woke people up to the capability of FM.

[TuningIndicator]

Of the three 242s I've restored; I've had only one with an intact OPTX.

I agree, Murphy were working with one hand tied behind their backs; being tied to Mazda.
But that's what I meant. They did an excellent job with what was available to them.
The evolution of Murphy VHF sets is, indeed, very fascinating.

I think the A242 is a beautiful radio, clean and very 'mod' looking.
.................That's why I love Murphys!

[JoshWard]

Very nice

I've wanted one of these for years then Howard offered one to me, being delivered Friday, can't wait

They're really attractive sets, a lot of Murphys seem to be, all the ones I've got are.

Must get some more!

Josh.

[JimMac53]

Josh, I've got a carcass of one if you need some spare parts, but its output Tx is gone already. I'm not too far from you, if you do.

[JoshWard]

Thanks for the offer, will let you know if I need anything

Josh.