Murphy Astra TV set 1961.

[FERNSEH]

I consider myself lucky to have purchased this interesting Murphy TV set. Made in 1961 it quite a modern set for me to have in the collection, it's only fifty-two years old.
So what's so special about the set for me to buy it? Well it is one of the rare ultasonic remote control versions of the Astra series. The two button remote control changes the channel and can mute or change the sound level. Unfortunately I do not have the remote control handset.
Starting the restoration: I use the approved HKS method, just plug it in and see what happens. It was not long before I saw results on the screen and this was before I even did anything to set!
Next three capacitors were changed, two 0.1mfd waxies in the frame timebase and the 0.01mfd line oscillator to output valve coupling capacitor.
Things are improving already, but it wasn't long before the boost capacitor failed.
That component replaced and set got even better, more picture width.
The channel change system packed in and some head scratching was needed to find the fault. The problem turned out to be the contacts on the "memory" wheel fitted at the back of the tuner unit, they needed readjustment.
There are seven notches around the edge of the wheel and these correspond to the seven positions of the tuner when a channel has been selected. The contacts close when the wheel rotates and open when it stops at the desired channel. That job done the set was almost ready to be signed off.
Other faults found: The GD10 sound detector diode had to be replaced, now there is plenty sound.
The HT voltage is bit low low at 200, the service manual shows 225 at the anode of the U193 boost diode. This set has a finned Westinghouse type HT10 rectifier. I might consider replacing it with a silicon doide. Only problem doing this is that the extra HT voltage can cause futher component breakdowns. I'm thinking of the line output transformer.
Now I have to make up a remote control. I have the remains of a Bush T22 ultrasonic handset which might do for the basis of a two button remote control handset.

DFWB.

[bobbyball]

That's a lovely set David. I saw one for sale a while back and wanted it but couldn't afford it in the end!!

It looks like new.

Fantastic film too ("Brief Encounter")...

Robert

[FERNSEH]

Hi Robert,
So far it has only taken four replacement capacitors and a repair to the remote control contacts to get the set going. No valves have been fitted during the lifetime of the set. The Mazda CME1901 CRT is so,so. I will replace it later with a CME1908.
It is a great film.

DFWB.

[vidjoman]

I liked those Astra sets, very reliable. Don't remember this remote version though. The manual tuner had the buttons arranged in a circle like the segments of an orange.

[System A]

Hi David.

What a super looking set, you"ve wanted one for a long time. As you say it looks as if its had an easy life. Now all you need is the 625 plinth for it to sit on. .

Regards, Gary.

[Heatercathodeshort]

That is a super rare receiver David. I have only seen one example and that was in 1964.
Twin channel remote amplifiers if I remember correctly receiving two notes from a mechanical handset similar to the early G8/9 remote. The Ekco of the same year and the Philco 'Selectorflash' did the same but used a light beam as a carrier. You may well have the only surviving example of of this model, one of the very last of the 'true' Murphys. I have the convertible version kindly donated by a Forum member [Thanks Tas]. It's a real cracker but suffers from contaminated oil in the line output transformer. I think cooking oil is an excellent replacement but the original oil needs to be well flushed out, a job for this winter. Regards, John.
PS Brief Encounter? More suited to your pink screened beloved Masteradio me thinks..

[FERNSEH]

Originally Posted by vidjoman

The manual tuner had the buttons arranged in a circle like the segments of an orange.

The Murphy "Compass" tuner.

I'm making some progress with the remote control. The Bush T22 remote control has been retuned to 43.5Khz which is the frequency of the channel changer in the Murphy. The sound muting is 46.5Khz.
The sine wave measured at the remote control output transducer is almost 150 volts p - p.
The remote channel changer system now works after some minor repairs and there is no reason why the sound muting should not work either. The 10Kohm cathode resistor is common to both sections of the 6/30L2 double triode relay driver valve. It's R619 in the Murphy circuit diagram. It had risen in value to 14Kohm.

The Bush handset will become the basis of a remote handset for this set.

DFWB.

[bobbyball]

This is very interesting to see.

Not wishing to "hikack" the thread I'll merely add the comment that I have a huge Pye TV/radiogram unit (NOT the "Trio") that has an ultrasonic remote control reciver and a multi-valve amplifier unit, Lord knows what functions on the (dual standard) TV chassis it actually controls. When I get round to looking at it I will start a thread on it.

In the meantime the Murphy chassis here does look pretty rare and good to see it suitably restored.

I shall also be digging out my copy of "Brief Encounter"!!

[Heatercathodeshort]

I despair..Two Forum members with a copy of 'Brief Encounter'. A much more robust film to demonstrate these fantastic Murphy receivers must be Fred Astaire and Ginger Rogers starring in 'Follow the Fleet' and with Irving Berlin to do justice to the sound.I took these pictures a few moments ago.

You will find a large number of the type of resistor used by Murphy Radio to have risen in value. Worth a good check over. The heater leads to the U26EHT rectifier tend to decompose where they exit the rubber cap seal but a stick rectifier will of course overcome this. A very well built chassis but typically Murphy mad. John.

[FERNSEH]

Originally Posted by Heatercathodeshort

PS Brief Encounter? More suited to your pink screened beloved Masteradio me thinks..

All right then.

Regards,
David.

[Brigham]

Originally Posted by Heatercathodeshort

I despair..Two Forum members with a copy of 'Brief Encounter'. John.

...And one with THREE copies. VHS, DVD and BluRay!

[Tazman1966]

It looks a goodie David. I don't seem to remember any foldover on the left of the picture on mine though. John, you'll have to confirm and good luck with the LOPT oil change It surely will be woth it with the brand new CRT that I put in it.

[dazzlevision]

Originally Posted by Tazman1966

I don't seem to remember any foldover on the left of the picture on mine though.

Hello,

I think the line foldover could be related to the fact this set has the "direct sync" line sync plug-in module. With the flywheel sync version fitted, you had some tolerance to centre the picture information within the raster using the line hold control.

There were some component value mods published in an early RBM "Service Skill" for the flywheel board.

I do like the Astra sets; I have the 19" Astra Mark 2 model V789, with VHF/FM radio. Luckily, I also have the UHF/625 converter plinth for it. Unfortunately, my LOPT has the usual problem.

Regards,

Dazzlevision

[Heatercathodeshort]

These were a great farewell to Murphy Radio but I think they did have a few problems with them in their early days.
They were quite a rare sight and didn't have a prolonged life as many of their contemporaries did.

The Mazda CME1901 gave one of the very best pictures but suffered a very short life. O/C cathode connection was very common and the emission soon dropped off. The LOPT also had a short life and was an expensive item from Murphy Radio. It could only be obtained from a Murphy dealer common with all Murphy spares, charged out at retail prices. [unless you knew a very friendly Murphy agent] .

Murphy would not supply non accredited Murphy dealers regardless of their standing or RTRA membership! The added expense did not lend the series good candidates for overhaul and resale on the reconditioned market. British Relay Wireless [BRW] were one of the few companies that specialized with Murphy receivers.

I have taken a couple of pictures from the screen of the Murphy this morning. It does have slight fold over to the left but I think this might be due to the contaminated oil causing a damping effect. It gets worse after 30 minutes as the width reduces.
It's interesting to compare the 700 series with the VU150 [not one of my favourites..]of only eleven years before. The CRM121B suffered exactly the same problems as the CME1901 and I cannot understand why Mazda or it's customers allowed this situation to continue for so long. The developments in just 11 years are very notable. Miniature valves, 114 degree tube, Band 3, 405/625 switchable timebase, a huge increase in gain held down with AGC, to say nothing of wireless remote control, the original 'Bluetooth'!

Pictures show foldover and comparison with the VU150. Regards, John.

[Focus Diode]

I had a V759 unconverted convertible model some 30 years ago which looked identical to John's set above when I was in Devon. I could only receive CH2 (North Hessary Tor) on it, CH9 (Stockland Hill) couldn't be tuned in. The CRT was very low emission unfortunately. I thought this model has the famed oil filled LOPT?

Cheers,
Brian

[FERNSEH]

The CRM1901 CRT is actually improving with use, getting brighter all the time.
However, the EHT voltage does go down considerably after a half an hour, perhaps a change of transformer oil will improve matters.
Evidently a line transformer of conventional construction was made as a service replacement by one specialist firm. Also, I believe British Relay Wireless used something similar, this fact needs confirmation.

DFWB.

[FERNSEH]

The remote control handset will have to emit short burst of signal to emulate the short pulse of energy created by the struck tuned bars in the orignal handset.
Actually I'm thinking of the two button Ferguson handset type T718. This 1970s ultrasonic RC would be ideal for the Murphy set if one can be found.

DFWB.

[bobbyball]

Got one somewhere if you get desperate!

[MALC SCOTT]

Hi David, what type of oil would you use?

[FERNSEH]

Hi Robert,
The Ferguson remote control handsets that would be most suitable for the Murphy are the T705 and T712. The T718 was in fact a three button unit.

DFWB.