Feb '67 Thorn / RCA Prototype CTV Demo & Article.

[SWB 18]

Hello,

Hope the attached press cutting from February 1967 will be of interest.

I had read about the set some time ago and came across the attached article on the web by chance, recently. Luckily I saved the file, as the original shortcut no longer works.

A little further information I have discovered is that the set was based on an RCA 25", working on simple PAL.

Can anyone add any further background on the set?

Regards,

Phil.

[System A]

Hi Phil
It looks like a thorn set to me.
Regards. Gary

[Colourstar]

It certainly looks to have a few 2000 series design touches about the crt presentation.... and is that a large Thorn logo on the front below the controls? I wonder what kind of tuner the chap is adjusting?

At this distance it's hard to imagine just how absolutely astonishing it would have been for a person seeing a colour television image for the first time, having previously known nothing but b&w. It must have been quite magical.

Steve

[Graham G3ZVT]

Originally Posted by SWB 18

Hello,

Hope the attached press cutting from February 1967 will be of interest.

I had read about the set some time ago and came across the attached article on the web by chance, recently. Luckily I saved the file, as the original shortcut no longer works.

A little further information I have discovered is that the set was based on an RCA 25", working on simple PAL.

Can anyone add any further background on the set?

Regards,

Phil.

No sign of a second tuner, so perhaps it was BBC2 only.

[Nuvistor]

Originally Posted by Colourstar

At this distance it's hard to imagine just how absolutely astonishing it would have been for a person seeing a colour television image for the first time, having previously known nothing but b&w. It must have been quite magical.

Steve

It was, I saw a Baird 25inch in the local Tech around Dec 1966/ Jan 67 displaying colour slides from Winter Hill test transmissions.

[murphymad]

The extract about this event from the Cussins and Light 'Golden Book'

Mike...

[Welsh Anorak]

I wonder which the 'very best sets' mentioned above were?

[ctc15]

Hi All The RCA chassis was probably a CTC17.
I have a copy of the RCA modification to convert it to PAL operation.
Keith

[Heatercathodeshort]

I wondered if it was the Thorn 1000 colour chassis that used 2 X PL500 mono line output valves in parallel. It is very illusive and not a lot exists on it's history. John.

[FERNSEH]

It's a Thorn development set alright. The ring around the VHF tuner will be the UHF tuner, rather like what the Philips K4 has.
Doubt very much if the Thorn laboratories used any imported TV chassis. They were well up to doing their own prototype designs. Consider the Ever-Ready transistor TV set. Nothing like anything else being made at the time.

DFWB.

[ctc15]

Hi All
In the report on the 1966 Earls Court television & radio show 22 to 26 August in the Practical Television Magazine the report for the :-
B.R.C group demonstrated a colour receiver. This uses valves throughout and a representative stated that at this stage it is extremely difficult to be dogmatic about the exact details of circuitry and presentation.
Was this the 1000 chassis? or was it a modified R.C.A chassis?
Keith

[dazzlevision]

Didn't Thorn have a tie-up with Sylvania of the USA at this time (and for some years previously)? Maybe they supplied some technical "know how"?

[ctc15]

Hi All
This is from The Wireless world Oct 1966 p533.

THORN -AEI announce that they are starting the large -scale production of
colour tubes at their Brimsdown, just North of London, factory in September. These 90' shadowmask tubes (Mazda V3503A) use rare earth phosphors and are fitted with integral metal suspension lugs. Initially production will be con- centrated on 25in rectangular tubes.
It is understood that scanning and
associated neck components for use with Mazda colour tubes are being developed in Britain by the Plessey Company. Although Thorn and
Sylvania of America at one time jointly owned a company (Sylvania- Thorn) for
the production of tubes in this country, this company no longer operates. Sylvania still have a financial interest in
the Thorn organization and a reciprocal
agreement exists for the exchange of
technical information on television
tubes between the two companies. Development of the new Mazda shadow - mask tubes and the design of much of
the production equipment performing key operations, has been carried out
entirely at the Thorn -AEI, Brimsdown,
laboratories.
Keith

[jayceebee]

I remember coming across Sylvania tubes in some Thorn schools receivers. The sets were a huge 27” model using a USA made 27AFP4 CRT with a 950 chassis fitted.

Is it just me but the set shown doesn’t look to be a 25”? I would say only a 19”.

John.

[ctc15]

Hi All
This was also on page p533.

This may have been one the reasons why Thorn took over Radio Rentals in 1968.

RCA Colour Tubes:-
A joint statement by the Radio
Corporation of America and Radio Rentals Ltd., has announced the formation of a new company to manufacture RCA colour television tubes in this country. Two -thirds of the equity in the new company, RCA Colour Tubes L.td., which initially has a capital of £1M, is being held by RCA Great Britain, on behalf of the American Company, and one third by Radio Rentals. A factory is being built at Skelmersdale, Lancs, and production is planned to begin in mid -1967. Initially some components may have to be imported for the 25in and 19in rectangular tubes to be produced. Although, of course, Radio Rentals will be using these tubes in their Baird colour receivers, it is intended that RCA Colour
Tubes " will offer its products freely to the whole trade on competitive terms." Tubes will be sold both in the U.K. and overseas. Incidentally, Baird receivers will be manufactured at Radio Rentals Bradford plant where considerable research has been going on in the
development of a colour receiver. The formation of the new company is RCA's first major move into the European colour market. It is understood that they are not contemplating set production in this country, such colour receivers as have been available so far have been imported by RCA Great Britain.
The directorate of RCA Colour Tubes is headed by D. W. Heightman (chairman) who is also director of engineering, Radio Rentaset Ltd. Dr. H. R. L. Lamont, director, European Technical Relations, RCA International Division, is the only other director named so far.

The Mazda tubes used in thorn 2000 3000 etc had made under Licence from R.C.A. on them.

Keith

[Welsh Anorak]

That might partially explain the somewhat bizarre (to our Mullard-centric brains) decoder in the Baird 700 series and the huge cabinets that they used.
I was wondering why the Mullard A63-11X and the Mazda CME2510 were, to all intents and purposes, identical except, perhaps, in lifetime expectancy. Surely there was some collaboration involved?
Mid-1967 seems pretty close to the wire for production, so I assume the first tubes were imported.
Meanwhile what was happening in Europe with their 25" tubes?

[FERNSEH]

According to the April 1966 Funk Technik bulletin the 25" rectangular shadowmask CRT registered as the A63-11X was announced by AEG and Telefunken.
https://www.radiomuseum.org/lf/p/fun...-ft/vol21num7/

https://www.radiomuseum.org/tubes/tube_a63-11x.html

The RCA CTC17A series introduced in 1965 employed the 25AP22 rectangular CRT.
The CTC19A series models with the 19" rectangular CRT type 19EYP22 came along in 1966.

CTC20A series models employ the round CRTs types 21FJP22A or 21FBP22A.

DFWB.

[FERNSEH]

From the 1966 Mazda valves and picture tubes data book. the Mazda V3503 25" development colour CRT.

DFWB.