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Old 30th Jun 2021, 9:12 am   #1
Heatercathodeshort
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Default Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

2 UGLY SISTERS. MURPHY V230 12" TRANSPORTABLES 1955.
When searching the loft for a spare part I discovered two black plastic bags wrapped up and sealed with parcel tape. Thoughts of some evil crime came to mind but I had a vague recollection that they were a pair of Murphy V230 receivers presented to me by a fellow enthusiast a long time ago.

At the time he informed me that unfortunately one had sustained an accident, and suggested that the inrush sound of air was evidence that the tube had lost it's vacuum.

It was time to sort these out and attempt to make one out of the two.

The 12" Murphy V230 is an incredibly over engineered piece of kit. A lot of aluminium is employed with complicated brackets for the preset controls. It was originally released by Murphy Radio in September 1955 being one of their first receivers to receive the new ITA on band 3, the first I believe being the V240/250 in late 1954.

With a list price of £36-19s-5d plus the purchase tax I don't know how Murphy made any profit from it but it did sell in large numbers. This particular example has the date 29-9-1956 pencilled on the inside of the cabinet and signed 'M'. He could not have imagined that sixty six years later that very receiver would still be capable of giving a very good picture.

In my opinion it is not a pretty baby more like a bloated Cod fish in keeping with Flash Gordon, space rockets and the general excitement of technology of the mid 1950's. The cabinet is manufactured from very solid compressed cardboard similar to Paxolin but more flexible. It is comprised of two sections that can be separated after removing the decorative clamps and bits that hold it all together. Once it is stripped of it's mucky frock, access is quite satisfactory for all service requirements.

Due to it's construction it tended to become scruffy. The case halves were painted old gold in a sort of stipple finish. With age the paint flaked off in places adding to the unattractive appearance. The side control knobs are passed through large holes that were tidied up with brown Bakelite rings held in place by massive, what could be called spiked lock washers that gripped the Bakelite rings from the inside. This was weak point number two. The retaining rings tended to spring off resulting in the loss of the decorative surrounds leaving the metal retainers to flop about inside possibly causing a short. It is very rare to find any of these in place when encountering a V230!

The rubber mask was a typical Murphy contraption built in two halves with a metal retaining frame bonded in the middle. The CRT fits neatly in a socket in one end with the implosion protection screen fitted into a groove in the forward section. After all these years the rubber tends to harden and crack rather like aged skin that only adds to the miserable appearance.

After my critical condemnation of the appearance of the little Murphy it is only fair to congratulate them on it's technical performance which this receiver is capable of, and can be seen later in the write up.

Murphy being contracted to Mazda had the usual problem with the Mazda range of TV valves. For some baffling reason they took a long time to produce a range of .3a valves that could be connected together with the CRT in a simple heater chain. The range employed in the Murphy clearly demonstrates the crazy situation. 30L1 [PCC84] 30C1 PCF80] 6L18 and the CRM124 CRT .3A. 20D1 U801 20P4 .2A and six 10F1 .1A. This required three chains wired in series parallel with dropping resistors to balance the load.

The LOPT does not follow Murphy practise being an open type of very high quality. No oil field spillage to clean up!

The tuner displays the very best of Murphy design. It used the conventional pair of valves, 30L1 cascode RF amplifier and 30C1 mixer/osc. The mechanism is four position and coils for any combination of TV channels could be easily clipped into place. A card hatch in the bottom of the cabinet allows access to the tuner without pulling the thing to bits. The coils are exclusive to Murphy using a wiper blades arrangement rather than the studs usually encountered in tuners such as the popular Cyldon. These tended to be more self cleaning than the studs proved by the very long period that elapsed before cleaning was necessary. The tuner is also incredibly stable proved by the removal of the fine tuner on all Murphy receivers from the V310 to the final 600/700 series.

The Mazda 12" CRT type CRM124 is one of their much better tubes [credit where credit is due] and enjoys a long life. It is an aluminised tetrode fitted with the duodecal 12 pin base and a 12.6v .3A heater. At last the old 2V triode with it's Mazda octal base has gone into history.

Gone also is the massive 20P1 line output valve [OK it was reliable] in favour of the much slimmer 20P4 the .2A version of the popular .3A 30P4. The line output stage is self oscillating and completely stable unlike the early versions of the later V310 series. The 20P4 valves were specially selected and coded GP for the V230 circuit.

The frame output stage is unusual with direct coupling employed between one half of a 20L1 triode and the 6L18 triode in the output stage. A 110V negative rail is used for biasing and brightness control offset. The other half of the 20L1 is the audio preamp. I know what your thinking but there is no trace of any frame buzz. Only Murphy..

The audio output valve is an RF pentode, a 10F1. After replacing the audio coupling capacitor that had a massive leak the quantity and quality of the sound from what is a standard RF amplifier type 10F1, amazed me. Even with the volume control on full there appears to be no audible distortion and must be delivering at least 1 watt to the 5" speaker. Considering the average output required for comfortable listening is probably no more than 250mw, there is more than enough to spare. I suspect that a good output transformer design has contributed to this.

O.K, so on to the switch on! My usual simple checks were carried out for HT shorts, a blown up U801 rectifier and any visible signs of distress. I hunted everywhere but the mains filter capacitor .1uf could not be located. The mains switch was gummed up but a touch of DeOxit soon freed it off. The mains voltage selector is clever but far too accessible to the customer. It can be adjusted for all mains voltages AC or DC and this led to problems when accidently set for the wrong voltage and would blow the mains fuse when set for DC. The arrangement continued for many years and often resulted in a service call when it had been knocked off position or twisted by mistake. The line output stage cover was removed to check for EHT and with continuity across the mains lead confirmed, I plugged it in to the isolated supply via my little neon indicator switch box.

The valves began to glow and with one eye on the U801, in it's own cage below the tube base, a very weak line whistle could be detected. There was a spark at the anode but a very weak one at the DC side of the U25 EHT rectifier. A quick cheque on the HT line suggested there was 'enough'.

The boost cap was located, a sloppy waxie .25uf. It read 100K! With this replaced the EHT increased and there was now a useable spark on the CRT final anode but there was nothing on the CRT. The CRM124 has an unusually low A1 potential wired directly to the HT line so a quick dodge was necessary to confirm that the CRT was capable of producing a display. Grid and cathode were shorted together with a test lead and low and behold a very distorted image appeared. The Mazda ion trap was adjusted and to my surprise produced a much brighter display. Rather odd because these Mazda designed ion traps do not move themselves. They are secured with a spring copper strip and it did not appear to have moved from it's original position under the plastic base protector/focus adjuster. Maybe just changed characteristics?

With the temporary link removed the screen returned to darkness. The brightness control adjusts between the negative 105V rail and the positive offset obtained via a 100K resistor, the vision limiter control, another 100K resistor finally to the HT line. The video is AC coupled from the anode of the video amp to the cathode of the CRT via a .1uf capacitor. This had a very heavy leak and was upsetting the offset negative voltage at the top end of the brightness control. The bottom end of the BC is connected direct to chassis with the slider to the CRT cathode. With the coupling cap replaced the brightness control operated normally 20and there were signs of a mangled test card just discernible.

There are very few capacitors needing replacement in this chassis. There are only two in the frame output stage and a couple of those torpedo shaped ones that look and no doubt feel they should have been born resistors. I will attach some pictures of the effects of these faulty components in the second part of this thread when I deal with the second ugly sister. The offending caps were replaced not forgetting the .01uf in the oscillator feedback circuit mounted on the frame output transformer. No resistors required replacement and were well within their 20% tolerance. The sync coupling capacitor was virtually S/C and was soon replaced as were the others with one of the modern, what could be described as 'perfect' capacitors obtainable from the BVWS spares dept.

After a degree of adjustment the chassis was now displaying a very good test card but the chassis was dusty and the main smoothing capacitor looked very tired with dried putty coloured puss deposited on it's rear end. It's little brother the 16uf+16uf was also suffering incontinence and with the CRT removed to gain easy access it was a simple matter to replace these with the nearest value components from my old stock. The mains filter capacitor was also discovered lurking behind the main block and was suitably neutered.

While the tube was removed I cleaned the component side of the chassis with the 1/2" paint brush and vacuum cleaner. The audio coupling capacitor was also replaced, a solid Hunts type that has served us well considering the years that have passed. I could not resist cleaning the fabulous looking CRM124 tube..

With the tube refitted, the ion trap reset and the joy stick picture positioner carefully adjusted, a very watchable picture was obtained on the original Mazda tube.
It was noted that the raster took a while to fill the screen area. This was due to a slow heating U801 rectifier. You have to remove the tuner valves to gain access to the U801 and even then it is a right fiddle! I found a few used ones in an odd box and they were all OK! [Switch on nervously..]An intermittent crackle on the sound was traced to a single broken socket pin 7 cathode of the B8A based sound IF amp. Fortunately the valve holders are of the best quality McMurdo and it took only a minute to remove the broken socket and replace it with one removed from a spare valve holder.

A soak test proved that everything was perfectly stable and it was time to sort out the shabby dress. Two of the Bakelite rings were missing but luckily the one with the smashed tube had the very two I needed to tidy up the case halves both of which required a good clean with 'FLASH'. The rubber mask was scrubbed with a nail brush and brightened up a bit. No doubt given time the cracks could be filled and repainted but that level of refurbishment may have spoilt it's original age and finish. How far do you go? Reassembly was not too bad once you have grappled with the two cabinet halves. It reminded me of those old photos you see when Victorian ladies were squeezed and tightened into Whalebone corsets, get the picture?

That is about it for the Ugly Sister number one but there is more to this tale to follow with Ugly sister two.

Pictures show: 1 Chassis removed from cabinet. 2 CRT and chassis side view. The aluminised Mazda CRM124 CRT. 4 The tuner showing Murphy Radio's exclusive tuning coil [biscuits] arrangement. 5 Voltage selector.

Conclusion. These Murphy models were excellent value for money and must have been very reliable. There are very few wax capacitors in fact compared with many chassis, not many capacitors at all in the economic circuit design. Stability is excellent and being equipped with one of the decent CRM124 Mazda tubes with a final anode voltage of 9kv, together with a quality line output transformer, represented excellent value for money. The overall RF gain is good with just one common vision and sound IF stage followed by single vision and sound IF amplifiers making a total of just three of the excellent 10F1 valves.

The case is a bit of a let down but the problem with all these early transportables is weight.. At 28lbs it is still a bit heavy for mum to move into the 'best room' for the Christmas and Easter holidays.

I would imagine that many of these were purchased as first time TVs. especially being fully equipped for the reception of the new ITA that launched the month and year that the V230 was released.

Regards, John.
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Old 30th Jun 2021, 9:15 am   #2
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

The LOPT and two off screen pictures. One with full workshop lights, the other in semi darkness. J.
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Old 30th Jun 2021, 10:29 am   #3
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

The second Ugly Sister was almost an identical twin. I had a feeling that I had picked up a V230 from the tip very many years ago and after a further search in the loft discovered yet a third one again wrapped up in black plastic. This was in fact the one pulled off the tip and once unwrapped discovered a much tidier example than the one I had just overhauled. This made a total of three V230's in all including the one with the smashed tube. I decided to overhaul the third example keeping the second scruffy one with the smashed tube for possible spares.

With the cabinet shells parted it was indeed much cleaner but I was a little apprehensive when I noticed that the original Mazda CRM 124 had been replaced by a rebuilt tube by HAROLD HARDING LTD of Bridge Works, Cowley, Uxbridge Middx. I have never seen another H.H. tube and feared the worst! I need not have worried.

It would be boring to repeat the details of the repair as it followed almost exactly the work carried out on the first Ugly Sister. In a couple of the pictures I have illustrated some of the effects of faulty key components.

It didn't take long to get signs of a picture. Again the U801 was very slow warming up and had to be replaced with another sorted from the odd box. As I have mentioned before it is always the burned looking babies rattles that are 100%! The nice cleaning looking ones usually blow the fuses.

The main electrolytics looked in good shape and remained cool so were left in place together with the 16uf+16uf dual can. The usual leaky caps were replaced and like US1 the I.F. decoupling capacitors are all of the best ceramic type and did not require replacement. [I hate that job!]

The resulting picture is a real credit to the guy that rebuilt that tube. There was no warm up delay resulting in a cracking picture from cold. It has a possible date code of 1962. The chassis is very tidy but must have been used heavily due to the amount of dust and general light muck especially around the CRT bowl and EHT connector.

It was necessary to rob the loudspeaker from US2. It is mounted on the top of the cabinet and acts as a funnel for dust, open fire soot, Budgerigar seed and fag ash. The voice coil was jammed on the magnet with the cone filled to the top with muck despite being covered with a fine black cloth and perforated metal grill.

As with US1 all the usual service requirements were carried out, tuner contacts, pots, valve holders were all cleaned together with a light chassis brush up with the 1/2" brush and vacuum cleaner.

The best of the cabinet parts were sorted from US2. The cabinet decorative retainers are quite clean and four were chosen for the final assembly. The Bakelite disks were all missing on this one but the retaining clips were discovered inside. I expect a set will turn up, parts usually do.

The end of the epic has resulted in two Murphy V230 receivers. Both are working very well and have remained stable for an eight hour run.

Pictures show; 1 The chassis from the rear. 2 Chassis side view showing the Harold Harding CRT. 3/4/5 Mucky chassis views.
John.
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Old 30th Jun 2021, 10:38 am   #4
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

Some more pics. 1 The effects of a leaky sync coupling capacitor allowing the video signal to randomly trigger the timebases. 2 Bad frame cramp caused by leaky coupling capacitors or linearity feedback loop capacitors in output stage. 3 Small picture slowly building to full size with slow H.T. rectifier. 4 Same shot with replacement U801 rectifier. 5 off screen picture 1.
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Old 30th Jun 2021, 10:41 am   #5
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

The remaining pics. J
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Old 30th Jun 2021, 10:42 am   #6
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

Another great write-up with wonderful analogies to glamorous dresses and the difficult decision whether to apply anti-wrinkle cream to the surround. I also loved the "couple of those torpedo shaped ones that look and no doubt feel they should have been born resistors."

The first mention of the 10F1 as the audio output made me look twice. It certainly seems to be a versatile valve.

The V230 isn't the most delightful looking set with its gothic arch frontal appearance.

Peter.

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Old 30th Jun 2021, 12:05 pm   #7
mark pirate
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

I last had one of these sets over 45years ago, I do remember the gold painted cardboard cabinet well, but forgot that they used a round tube

Murphy sets always were excellent performers, even though the designs were quite odd!

I also had an Ekco portable set with a similar cardboard cabinet, that from memory, was silver, I guess the Murphy is the older set?
Both were certainly not attractive looking sets!

I have seen a few of these come up on auction sites, but not been tempted due to the flimsy & fragile cabinet.

I certainly prefer the Ekco TMB 272 as far as portables go.


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Old 30th Jun 2021, 12:18 pm   #8
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

The Ekco you mention must be the 1958 TP308 14" with rectangular tube and FM radio. I think they look quite smart when compared with the V230. The Ekco chassis was basically a folded up version of the T330 and gives an amazing picture. J.
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Old 30th Jun 2021, 12:51 pm   #9
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

Quote:
The Ekco you mention must be the 1958 TP308 14" with rectangular tube and FM radio.
Hi John, you are indeed correct.
More of a looker than the Murphy, but not by much!
Even all those decades ago, I was amazed by the use of pressed card as a cabinet, especially on a portable set that will get bumped around.

I remember both my Murphy & Ekco sets had damage to the cabinets, the Ekco was particularly damaged underneath & the rear.
Both probably came from the scouts jumble sales, my main source of sets in the early to mid 70's!


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Old 30th Jun 2021, 2:39 pm   #10
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

Quote:
Originally Posted by Heatercathodeshort View Post
The Ekco you mention must be the 1958 TP308 14" with rectangular tube and FM radio. I think they look quite smart when compared with the V230. J.
I agree and had one many years ago. Controls angled on the top. Much nicer than the Murphy competitor.

Peter
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Old 30th Jun 2021, 6:18 pm   #11
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

Nice work on those Murphy’s, John! I have one lurking under the bench, came as part of a deal with an Ekco AC85 radio, basically if I bought the radio I got the TV with it, just for showing an interest! I had a quick go at getting it working, but it looked like the tube was well past it, so I gave up maybe I’ll give it another chance sometime in the future!

Regards
Lloyd
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Old 30th Jun 2021, 7:00 pm   #12
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Default Re: Two Ugly Sisters. 12" Murphy V230 transportables. 1955.

A Mullard tetrode will fit nicely. A MW31-16 or MW31-74. Same base and a bit of room to fiddle with. John.
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