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Old 18th Sep 2017, 9:39 am   #21
FERNSEH
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Default Re: TV developments 1960.

Quote:
Originally Posted by Brigham View Post
Was it Sobell that had the push-buttons in a circle, with a centre pointer turning towards the one selected?
You would see such gimmicks on American cars of the day.
That was the Murphy "Compass" tuner which appeared in 1961 in the Astra series of models.

DFWB.
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Old 18th Sep 2017, 10:13 am   #22
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Default Re: TV developments 1960.

Quote:
Originally Posted by FERNSEH View Post
that's the one, although didn't experience too much trouble with the tuner.
I didn't have too much trouble with them either, occasional valve, clean and that fine tuner rod.

One thing I did find that broke them was pressure on the channel change knob, if you put the set on its face without taking the weight off the control it would break the tuner. Perhaps I was unlucky, only did it once but was quite careful about not doing that in the future.

I usually found them in Ferranti sets, 11u type chassis, the Ekco sets used a push button tuner.
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Old 18th Sep 2017, 10:36 am   #23
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Default Re: TV developments 1960.

Quote:
Originally Posted by FERNSEH View Post
That was the Murphy "Compass" tuner which appeared in 1961 in the Astra series of models.
Like this set, the Murphy V753A:
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Old 18th Sep 2017, 11:18 am   #24
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Default Re: TV developments 1960.

Was the Astra series not one of their best models, the earlier 300 and 400 ranges (think those are the correct numbers) were excellent TV's, shame about the oil filled LOPTX those sets though.

The Astra range did not seem as good, not that I saw many but the Bush TV105 and 115 seemed much more solid. The first RBM Murphy I saw was the TV125 chassis, I could never remember the Murphy model numbers.
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Old 18th Sep 2017, 11:35 am   #25
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Default Re: TV developments 1960.

That Murphy V753A is the exact set that I had in my bedroom as a young teenager in the early seventies, bought from a local TV shop, ex rental probably. It was a great picture on 405 but I always wondered how I could convert it to receive UHF as well. It had a 405/625 switch right at the bottom (fixed with a screw so you couldn't move it, I seem to remember) but when I took the back off I couldn't see how it could be done.
The Bush/Murphy set we had downstairs had been converted by the service guy by putting in a new UHF Tuner and I think a different IF panel and I hoped the same could be done to the one I had but I never did get BBC 2!
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Old 18th Sep 2017, 11:49 am   #26
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Default Re: TV developments 1960.

I think the Astra range was one of the "convertable" sets, made when no one really new what was going to happen with the TV standards.
There may have been kits around to convert but I doubt many were completed, the sets would have been three years old when BBC2 first came out, longer in other regions. Once over three years old and the BBC2 programs not popular many would have not bothered with the expensive change. Possibly 3rd of the cost of a new TV that had full UHF 625 capability.

I probably mentioned before that the only conversions I did was to fit a tuner and aerial, no one wanted their older sets converting.
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Old 18th Sep 2017, 12:29 pm   #27
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Default Re: TV developments 1960.

Here is a picture of the Astra range UHF converter unit. There were four basic versions of this: 19" and 23" and the electronics inside was slightly different for sets with VHF/FM radio.

In the Astra Mark 2 range, all that was necessary, was to screw the converter unit to the underside of the TV, knock a pre-punched circular hole out of the bottom of the back cover and plug the Octal plug into the now revealed Octal socket. The Murphy converter was one of the better units produced by UK TV manufacturers, as it had plenty of gain (3 x 6F23 vision IF stages).

For Astra sets without a flywheel sync PCB fitted (they plugged in) (model number ended with an "A" if the set was factory fitted with flywheel sync), the converter unit included a replacement line flywheel sync PCB, which was necessary for UHF reception.

Many years ago, I converted a Murphy V753 and the 625 picture was excellent.

I do like the Murphy Astra chassis, especially the Mark 2 sets. When fitted on the magazine style stand, they looked very nice and the converter sat below the set blended in. The chassis design allowed the cabinet to be nice and slim.

Electrically and mechnically, the chassis exhibited all the usual Murphy "eccentricities", but it worked well, especially the "deluxe" versions, with built-in VHF FM radio facilities.

The equivalent Bush sets (TV105 and TV108) were of more conventional and solid design, both internally and externally. They also worked very well.
Attached Files
File Type: pdf Murphy Astra UHF converter plinth.pdf (723.3 KB, 143 views)
File Type: pdf Murphy Astra UHF converter plinth 2.pdf (758.2 KB, 103 views)

Last edited by dazzlevision; 18th Sep 2017 at 12:38 pm.
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Old 18th Sep 2017, 12:36 pm   #28
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Default Re: TV developments 1960.

Thanks for that, do you know the price of the unit? There is a lot in it so it wouldn't be cheap.

That's for the 1962 Mk2 so only a couple of years for BBC2 in the London area, may have been worthwhile for those who wanted BBC2.

Edit. Just seen the second PDF, 13Gns, not too bad if it included PT.
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Old 18th Sep 2017, 3:03 pm   #29
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Default Re: TV developments 1960.

Here are details of the Murphy conversion kits for the earlier Astra Mark 1 series (V6xx model numbers).

A lot of extra work was required, as a lot less provision for conversion was made during the manufacture of these sets (as was the case for sets from the other UK manufacturers, apart for Pye and Ekco group).

Apart from fitting the converter plinth unit, conversion also required:

fitting the Octal socket and wiring

fitting an additional section to the 405-625 slider switch on the main chassis and associated new wiring

making a hole in the base of the back cover, for the converter's Octal plug

several other individual component additions/changes/deletions.


So, this conversion would take much longer and therefore cost more to implement. No wonder so may unsold stock conversion kits appeared in Manor Supplies later in the 1960s!

As Murphy chose not to have all valves in the converted sets "hot", there was a delay when switching between 405 and 625. I think Murphy published a mod to overcome this in an issue of "Murphy Service News".

Murphy also offered a kit to allow converted sets to operate on VHF/625 aerial systems (e.g. block of flats) and this involved more significant mods.
Attached Files
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Old 18th Sep 2017, 4:01 pm   #30
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Default Re: TV developments 1960.

Another good source of information on TV development from this period is the Newnes "Radio and Television Servicing" books.

Unfortunately I have a bit of a gap in my set of these books for the first half of the 1960s except for the 1961-62 volume.

Here is a brief outline of what is discussed there.

Transmission Standards.

The first switchable and convertible sets for 405/625 operation were shown at the 1961 Radio Show.

A switchable set is defined as having all the circuitry for 405 and the expected 625 system already present; each being selectable by means of a switch.

A convertible set is defined as one built in such a way as to receive 405 transmissions but to be easily converted to receive 625 with the minimum of tools and work.

This is followed by a comprehensive discussion of the problems and techniques associated with dual standard operation.


UHF Tuners

UHF tuners are discussed and how very different they are to the then familiar VHF tuners.

Band I/III Tuner Trends.

The latest VHF tuner designs are discussed along with associated new valves such as the PC97.

Transistor Television Sets

A discussion of new all transistor models.

Transistor Television Receiver Servicing.

A discussion on the pitfalls of servicing transistor sets when compared to sets using the more robust valve.

Field Timebases

Service engineers are encouraged to use the international term "Field Timebase" and not the old British term "Frame Timebase".

New field timebase circuits for wide angle CRTs are discussed.

Improved Rectifiers.

Silicon rectifiers had been more popular in the USA because the 400volt PIV devices then available were adequate for USA mains voltages. 800v PIV devices were now becoming available making them suitable for UK mains. The then new PY33 valve rectifier with its (10v) lower forward voltage drop is discussed.

Picture Tubes.

Here new CRTs are discussed with

1] Squarer, flatter screens.
2] Improved contrast ratio.
3] Bonded implosion guards.

Colour Television.

Experimental broadcasts by the BBC of the NTSC colour system modified for 405 line operation.

BBC 405-line System.

A simplified explanation of the system is offered.

Colour Servicing.

An argument that with a little theory training and a few bits of extra test equipment, servicing colour sets should be as straightforward as servicing monochrome sets.

Remote Control Systems.

Finally the state of the art in the field of wired, ultra-sonic and visible light remote systems is discussed.
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Old 18th Sep 2017, 4:48 pm   #31
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Default Re: TV developments 1960.

In 1960 two all transistor TV sets were announced, the Pye TT1 and the Ferguson "Transvista" 743T. OK, maybe not quite all transistor because valve EHT rectifiers were employed.
December 1960. The first 19" "square screen CRT first appeared in a UK made TV in the form of the Ultra V1980. CRT was the Mazda CME1901, 114 degree deflection angle.

DFWB.
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Old 18th Sep 2017, 6:11 pm   #32
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Default Re: TV developments 1960.

The same with US all transistor TV sets, the Philco built in 1959 and the Motorola 19" in 1960, both using valve HV rectifiers.
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Old 19th Sep 2017, 8:59 am   #33
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Default Re: TV developments 1960.

The Murphy UHF conversion unit worked very well. Plenty of gain, a good conversion and could be done in 4 minutes!

Unfortunately not many of the 600/700 series survived. They employed [but they should have been sacked] the Mazda CME1901/2301 early squared off cornered tube. It was a total disaster lasting just over a year if you were lucky.

Add to this the oil filled LOPT that failed, both expensive components and the rather poor resistors. As Frank has mentioned they were very unpopular for reconditioned sales due to spares expense. The parts added up to more than you could sell it for!

Interesting today of course especially the remote control models that filled the craze during 1960/61. John.
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Old 19th Sep 2017, 9:48 am   #34
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Default Re: TV developments 1960.

Yes, I have to agree about the Astra chassis "Mazda" CRTs and oil filled LOPTs, plus the "Erie" (IIRC) dipped carbon composition resistors. They all contributed to unreliability.

I would think that Murphy dealers must have been quite pleased when the Rank takeover of Murphy Radio Ltd, saw the next range of Murphy sets (the V8xx series) fitted with the Bush TV125 chassis, which must represent the "peak" of hand wired TV chassis development.

Having said that, I do like my Murphy V789A Astra Mark 2 set, which incorporates high quality VHF/FM radio (with AFC and double IF conversion for better selectivity), gated vision AGC, flywheel sync, automatic contrast adjustment with room lighting changes and a more refined cabinet. It no longer has a Mazda CRT in it, of course! I do have the correct UHF conversion plinth for it, but have yet to actually fit it.
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Old 19th Sep 2017, 1:21 pm   #35
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Default Re: TV developments 1960.

Interesting to hear how the Murphy Astra sets, like the one I had years ago, could be converted, I didn't think at the time about a plinth that it could stand on with the extra electronics in it.
My one worked very well for years on 405 but eventually the picture got more narrow as time went on.
If I remember correctly ,I managed to work out it was a large metal rectifier at the front of the chassis and just about had the knowledge to replace it with a silicon Diode I had found somewhere and it worked well again.
Unfortunately I didn't have the knowledge at that age to put any resistor to make up for the more efficient rectifier and eventually the set packed up!
Steve.
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Old 19th Sep 2017, 1:34 pm   #36
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Default Re: TV developments 1960.

Apart from the V789 and V783 (Astra Mark 2 sets with VHF/FM radio), other Astra model used a metal rectifier, which over time developed a high forward resistance, causing the HT line to drop and the "small picture" symptom. It was situated at the front of the chassis, under the CRT, next to the HT smoothing choke.

The V789 and V783 used two "Ferranti" Silicon rectifiers in series (I assume two, as one didn't have a high enough Peak Inverse Voltage - PIV - rating).
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Old 20th Sep 2017, 4:56 pm   #37
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Default Re: TV developments 1960.

Hello,

Here are some photos of two VHF turret tuners used widely in the early 1960s.

The larger one, with (safety isolated) aerial input socket at the rear, is an SA8148, made by Ekco (E K Cole Ltd) and is almost the final incarnation of a design that began with their first multi-channel Band 1/3 sets, using 30L1 and 30C1 valves.

The tuner pictured uses two Mazda designed frame grid valves: 30L17 and 30C17, which provide increased gain. The pentode section of the 30C17 (mixer) is variable-mu, to allow AGC to be applied. This tuner also has the facility to act as an IF preamplifier for the UHF tuner. The UHF tuner's IF output is connected to the coax socket mounted on the top front of the tuner. A special set of UHF "biscuits" is fitted for this purpose (but not in this example). When set in the UHF position, the VHF local oscillator is disabled.

The Ekco tuner is rather big, compared to others available by this time and an example of a compact valve VHF tuner is the USA designed (but made under licence in the UK) MT6, which was very popular with Thorn/Ferguson. This uses the PC97 and 30C18 frame grid valves and has a UHF IF preamp facility. The UHF biscuit is the longer one (and can just about be seen, near the contact fingers). This version of the MT6 has the preset fine tuning system at the rear. Those white plastic "screws" were rather fragile and the threads tended to strip.

The MT6 was used in many Ferguson convertible/dual standard sets of this era (700 Phase 2, 800 and 850 chassis) and also made an appearance in the Pye 11U / Ekco T418 series of sets (the first common Pye/Ekco TV chassis).

I'm a fan of the final incarnation of the Pye 11U chassis, with two frame grid valves in the vision IF stages. When fitted with the Ekco VHF turret tuner, the overall sensitivity of the chassis is at its highest, even better than with the MT6 tuner (according to the relevant Pye service manual). The UHF tuner's IF output is amplified by both valves in the Ekco tuner, rather than just the mixer pentode in the MT6 and this may well be the reason.
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Old 20th Sep 2017, 8:06 pm   #38
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Default Re: TV developments 1960.

Although by 1960 miniature tuner units were available in the form of the Fireball and various turret tuners from AB Metal Products many TV manufactures continued to used the large Cyldon Type C turret tuner which actually originates in the late forties as the American Standard Coil tuner. Mustn't forget the miniature incremental switch tuner made by Pye, that was a tiny unit.
Ekco continued to use their own large turret tuner well into the early sixties, later on it was used in many Pye Group TV sets, the model 11 for example.
Remote control TVs were the big thing in 1960 but many were just the simple long cable systems, nothing clever about that. Dynatron went one better and introduced a cordless ultrasonic remote control system which offered the user channel change and volume up and down. However, even more advanced remote control systems were available in America two years earlier.
Introduced a the Radio Show in 1960 the HMV model 1920 offered a cordless remote control system. The 40Khz signal from the "pinger" remote handset offered the viewer channel changes plus a facility to switch the set to standby when a predetermined position on the tuner had been set.
Not certain about intro date the Murphy remote control system which was available for certain Astra models, was it 1961?

DFWB.
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Old 20th Sep 2017, 8:09 pm   #39
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Default Re: TV developments 1960.

Quote:
Originally Posted by FERNSEH View Post
Mustn't forget the miniature incremental switch tuner made by Pye, that was a tiny unit.DFWB.
Was that the one with the self expanding coils...!:

http://www.r-type.org/timeline/time-124.htm

Lawrence.
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Old 20th Sep 2017, 8:27 pm   #40
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Default Re: TV developments 1960.

"Here the designers have saved a great deal of space by introducing a new miniature incremental inductance tuner (made by HDF, Ltd., of Lowestoft"

I remember the HDF company of Lowestoft title but was it just a subsidiary of the Pye Group of companies?

DFWB.
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