Murphy V114 9" table model 1947

[Heatercathodeshort]

This 9" table model Murphy V114 was the first post war television receiver released by Murphy Radio of Welwyn Garden City in 1947. It follows closely the V86 range released in September 1939, very few of which were sold to the public due to the outbreak of WW2 during the radio Show at Olympia on Sept 1st.

Due to government war contracts, Murphy badly needed the space occupied by these redundant receivers and was offered storage space by a large Murphy dealer at High Holborn in London.
The few that survived the Blitz were allocated to Murphy dealers within the television service area in time for the reopening of the service in June 1946. [They were actually collected in person by the dealers themselves]

A year later the long awaited first post war model the V114 arrived and was eagerly received by the loyal Murphy dealers.

This particular example has quite an amazing history. It was discovered in a farm cottage situated in Wellingborough Northamptonshire where it had spent it's entire working life.
It is fitted with the Murphy one valve pre-amplifier still attached to it's back, an interesting addition as the signal from Alexandra Palace was very weak and unpredictable
at such a distance. Northamptonshire was very much a fringe area for television back in 1947.

The guy I collected the V114 from was very interested in the history of the receiver as he had known it's owner, now living in a care home, since childhood.
He remembered the four element Band 1 array on the chimney stack and watching programmes on it when he was a small lad. He was eager to show me the actual farm cottage and kindly drove me the few miles to the small village to take some pictures.

Three of the unoccupied terraced cottages were considerably delapidated and it was in one of these that the Murphy was discovered.
In view of this It was almost a miracle that the V114 had survived in such good physical condition.
The room where the V114 was discovered is shown in the pictures. Piles of rubbish with a hole in the roof alowing daylight to enter.

The Murphy must have given good service for over ten years as the remains of a console version of a model V410 [1958/9] was discovered under a pile of rubbish.
I will post the restoration as soon as I can write it up. John.

[Colourstar]

What a fascinating story John. I always enjoy a restoration all the more when you know the history of the set you are working on. You can imagine the glow from the Murphy illuminating that little room back in the early 50s, no doubt with the occasional flicker from a coal fire and a tinkle of bone china tea cups...

It sounds like damp ingress may be a factor on your Murphy - How well has the cabinet survived?

I shall await the next thrilling chapter with interest...

Steve

PS- Was the V410 console beyond redemption? Quite a rare beast itself.

PPS- Do the abandoned 78s give a clue as to the previous owner's musical tastes...?

[Heatercathodeshort]

Originally Posted by Colourstar

It sounds like damp ingress may be a factor on your Murphy - How well has the cabinet survived?
I shall await the next thrilling chapter with interest...
PS- Was the V410 console beyond redemption? Quite a rare beast itself.
PPS- Do the abandoned 78s give a clue as to the previous owner's musical tastes...?

The cabinet is incredibly good Steve.
The V410 was just the cabinet. I could not find any chassis parts.
The Dam Busters and the Coronation Scot plus some 1930's dance bands.
John.

[Colourstar]

Hmm, a Murphy with missing innards and a copy of The Coronation Scot... sounds like a case for Paul Temple. Cue the music!


Steve

[Lloyd 1985]

Interesting story, I don't live that far from Wellingborough!

Got any photos of the set?

Regards,
Lloyd.

[Heatercathodeshort]

Down boy! Plenty of pics to post. You will have to wait and bite your nails!
[ASAP Lloyd, John]

[McMurdo]

My last acquisition was a V410 in near-new condition.
Looking forward to your V114 restoration John, it's in the best hands I think!

[Tazman1966]

I look forward to the next instalment John

[FERNSEH]

Hi John,
Murphy's first post-war TV set. An Interesting design feature of these V114 and V116 models is the double-diode first detector. Seemed a good idea at the time but it was replaced in later models by a conventional triode-heptode frequency changer valve, a Mazda 6C9. The basic chassis was modified for the V120C for flyback EHT. Same mix of 4 and 6.3 volt valves. Strange line timebase booster diode heater supply arrangement. The Mazda U403 heater is supplied from the 200 and 240 volts taps on the mains transformer primary
The next model was the V180C which was the subject of two separate topics.
This set has addressed much of the strangeness of the earlier models. All the valves are Mazda 6-3 volt types except for the U282 booster diode.
All these sets employ thyratron timebase oscillators, Mazda T41 in the V114 and V120C and the 6.3 volt 6K25 in the V180C.
Once one becomes accustomed to the unusual circuits of these Murphy receivers you soon come to appreciate how good these sets can be.

DFWB.

[Danny]

Wow, lucky the vandals didn't get the V114.

As for the V410 its insides were possibly removed and taken to the local TV man for repair but never returned.

If you are going to the NVCF I have a Murphy going on my stall, so you could get new insides for the V410 and reunite the pair again.

Danny.

[Heatercathodeshort]

With the V114 on the bench it was time to assess what lay ahead. The back was removed to expose a chassis that had not seen mains applied for well over half a century.
It must have felt a little frightened in such strange surroundings but reassured by the workbench and vintage test equipment, memories of that service workshop back in Wellingborough in the safe hands of the friendly Murphy Dealer.
It was now rescued from what it thought was to be it's final resting place, where it dreamed of it's early pioneering days of Test Card 'C' with it's pleasant music, The Coronation day and Sylvia Peters to keep it company in those far off days of austerity in the Great Britain of the 1940's and early 50's.
It must have thought it's flow of electrons were long gone now, just an old man's memory.
The designers back at Murphy Radio in the late 40's and it's Churchillian military construction ensured it had one final battle to win.
It was time to resurrect this old soldier, place his battle worn body on the operating table and apply the anesthetic.

The preamp was disconnected from the supply tag board to the left of the drop down chassis and the back safely stored. [Actually thrown under the bench..]
It was covered in dust and muck with cobwebs, dead insects and wood worm dust but otherwise in surprisingly good condition.
With the four chassis bolts and the front control knobs removed it was a simple matter to slip the massive tank like chassis from it's wooden cloak.
I did not wish to upset anything at this point with a view to getting 'first light' with a minimal amount of disturbance.

The V114 follows conventional post 1938 circuit design. 6F12s the Mazda version of the well known EF91are employed for RF amplification, sound and vision IF amplifiers and video amplification. A 6L18 triode sits in the local oscillator socket, a valve more often encountered in the Ekco 'Spot Wobble' oscillator or a frame output valve in Ekco and Plessey chassis. A double diode 6D2 acts as a frequency changer with it's cathodes separately supplying the vision and sound IF stages. This is an unusual circuit and off the top of my head I can't recall another receiver that does it this way.
A M.O. based HL41DD detects the audio and offers a stage of AF amplification. A DD41 provides a very effective sound noise suppressor before the big PEN45 audio output valve supplies more than enough sound to a large forward facing loudspeaker.
Another rather strange arrangement comes to light when you see another DD41 acting as sync separator the anodes of which are strapped together. Line sync pulses are taken from one anode and the frame sync via a filter network are supplied to the T41 thyratron field generator. Another PEN45 follows this providing frame output.
The line time base is another T41 generator followed by a fat PEN46 output stage. Both timebase circuits are simplicity themselves helped in the case of the line output stage by the lack of need to produce the EHT supply via the line flyback.
HT is provided by another frightening looking Mazda rectifier the UU8. EHT comes via a U22 from a high voltage winding on the mains transformer. It should be marked with a skull and crossbones.. The U22 has a very slow heating cathode to ensure that the timebases are up and working before the EHT is applied to preventing possible screen burns. The picture tube is a Mazda CRM92 2V triode supplied with around 5KV.
A tiny B3 based 6D1 [EA50] takes care of vision detection mounted on the back of the receiver unit all alone in the top right corner.
The V114 employs a mains transformer for the EHT supply rectified by a U22 rectifier and smoothed by a .1uf 7000v working capacitor. A chain of five 4.7m resistors across the supply act as a bleeder network to discharge the .1uf capacitor and provide a degree of stabilization. This completes the lethal arrangement.
A meter cheque revealed a 500k short across the massive TCC 'Visconol' smoothing capacitor, not good news for the mains transformer.
Removing the filthy U22 revealed a very smoky burnt interior that had obviously been asked to supply far more current than the 1M/A the Mazda design engineers had catered for the poor thing!
Every 4.7m was O/C presenting a very hazardous situation for anyone tackling problems with the EHT supply circuit and this was duly noted.

With the capacitor disconnected it was time to apply the mains and see what sort of sparks and flames this little beastie could produce. A meter check across the HT line miraculously indicated the lack of any shorts. True to my colours the UU8 full wave HT rectifier was removed together with the top cap anode connection to the U22.
I plugged it in.....John. [Pictures show chassis and cabinet as received upon first removal from cabinet.]

[Lloyd 1985]

Great story so far! the chassis looks very similar to my V180C, apart from the mains EHT bits!

Regards,
Lloyd.

[mark pirate]

It certainly is built like a tank, fingers crossed that the CRM92 still has some life left in it....

Mark

[Peter.N.]

That looks in pretty good nick - apart from the cobwebs, will be interested to see how it goes. Haven't seen a UU8 for many years.

Peter

[brianc]

I have virtually a full set of spares for the V114 - I scrapped a V116 because of a cabinet that must have been a woodworm Butlins! Just let me know if you need anything.

[Halfabee]

This is better than a classic Dr Who cliffhanger, the suspense is killing!

[AidanLunn]

The TV probably cost more to buy than a Hartnell episode of Doctor Who cost to make!

[Heatercathodeshort]

I decided to retain the original cotton covered rubber mains lead. It was still perfectly serviceable and part of the original manufacture.
With the mains applied for the first time it was more like Dr Finlays Casebook than The Adventures of Flash Gordon.

The valves and CRT heaters began to glow and there were no nasty sparks from the EHT section of the mains transformer but was it producing any EHT voltage?

WARNING! If you are dealing with a receiver that derives it's EHT from the mains supply and you are not familiar with the circuit arrangement employed, leave it alone until you have obtained advice from someone who will advise you of the potential dangers you may encounter and how to deal with the hazard.

It is unsafe to take voltage readings from EHT transformers. The actual circuit is about as simple as it gets and any break in the EHT winding will produce arcing, sparks, overheating and possibly flames, all very visible and obvious. The EHT smoothing capacitor will have a value of around .1uf at 7kv working and will retain a very dangerous charge for a long period if the bleeder network usually consisting of a chain of 4.7m resistors is O/C. [They always are!]
The EHT capacitor is frequently a large Bakelite TCC 'Visconol' that by now, sixty years on and fifty years past it's design life, will be leaking like a sieve and must be either replaced or disconnected for the first tests.
These capacitors if leaking will produce great heat leading to a violent explosion of the sealed Bakelite case, sending fragments of sharp innards and unknown insulating oil, everywhere....
Note this will only occur with mains derived EHT due to it's low impedance high current source. Leaking or shorted Visconols employed with flyback EHT safely collapse the EHT supply thus removing the overheating danger.

I played it safe leaving the UU8 H.T. rectifier on the bench and reconnected the top cap of the U22. I switching on again and waited for the slow heating cathode to come to life.

Moments later I was rudely awakened from my slumbers by a rich argon coloured flame from the valve's interior. Before I could switch the beast off, the bench trip did the job for me. [What fun!]
The Visconol had been disconnected so there were only three possibilities. Either the CRM92 had an internal short, [very unlikely] the heater winding's insulation had broken down to the adjacent winding or core, [possibly, due to the 12kv peak inverse voltage present] or the U22, back in the 1950's, may have been despatched to the planet Mars, propelled by that nasty Visconol.

It was time to visit the valve store to unearth two U22 EHT rectifiers. One looked tatty externally but reasonably clean inside, the other was a brand new 1940's example unopened and was far too nice to risk in the faulty Murphy!
The scruffy example was fitted and with my eyes fixed to the valves internal anode bell, flicked the switch. The heater began to glow and to my relief, no blue discharges and all seemed well.

With an electromagnetically focused triode tube supplied with heater and EHT voltage, [Mains derived, not flyback] an out of focus 'blob' of illumination should be observed on the screen face. It will not be effected by any of the preset controls of course due to lack of the H.T.
If it is bright and clear the chances are that the tube has good emission but if it looks more like the surface of the moon with pitted black areas denoting poisoned cathode areas, it is probably in very poor condition.
Sure enough the V114 produced it's first light. The blob was reasonably bright but was covered in large black pits revealing a tube in very poor condition.

Removing the CRT base and lowering the IF/sound and video chassis revealed a pale white getter, a far cry from the shiny black/grey it should resemble.
I came to the conclusion that the results were encouraging enough to carry on with the next stage of the restoration.

Pictures show: The cabinet back complete with AP preamplifier. Murphy service manual cover. [Three versions of which were required to obtain all the information needed]
Untouched side view as obtained. The 'Blob' [Long exposure] The massive Visconol and the burnt out U22 rectifier. It is starting to get interesting. John.

[mark pirate]

Going well so far, shame about the Mazda airbag though
I wonder when the set last saw a picture, and what programme?

Mark

[Lloyd 1985]

It's certainly looking promising!

I picked up a nice looking Ekco T.U.211 at the NVCF, unfortunately that looks to have a duff tube, the getter looks kind of transparent, and slightly white. The heater still glows though! I have a tube in a TV22 that also had the same look to the getter, but that tube gave a cracking picture! Until the LOPT packed up...

Regards,
Lloyd.