Round-screen colour television?

[Dave Moll]

The only one I know of is the Pye experimental 405 NTSC in the possession of "Fernseh".

I suppose the Americans must have produced them, considering that I understand that was the origin of the above CRT.

[Kat Manton]

Hi,

Originally Posted by Dave Moll

I suppose the Americans must have produced them, considering that I understand that was the origin of the above CRT.

Correct, since the US had colour long before Europe, the 1954 RCA CT-100 being one of the first colour sets on the market. Plenty more to drool over here.

The only European set I know of is the Philips K4 (made for export to Canada I think) though some were used in Europe and the UK for experimental purposes.

I for one would like to import an early round-tube set from the US but that'll have to wait a while. I suspect it'd prove expensive...

Regards, Kat

[ukcol]

When, in 1969, I took the City and Guides "Colour Television Principles" certificate which was a 1 year course tacked on the end of the RADIO AND TV Servicing course we used round screen RCA sets for the practical work.

This was at Southgate Technical College in North London.

I've not seen a round screen colour set since.

[mickjjo]

Originally Posted by ukcol

...... RADIO AND TV Servicing course we used round screen RCA sets for the practical work.
This was at Southgate Technical College in North London.

Well I know what became of those sets .... . In around 1978 I helped a friend collect two RCA 21" "color" sets along with a prototype Ekco 21" colour console, (serial No 1 ), from that college. I kept one of the RCA sets, which date from about 1963, until about 20 years ago. They were all valve monsters in woodgrained steel cases, adapted for 625 line NTSC .
I remember having to remove the chassis to get it through the front door . With a few mods I did get a picture of sorts, but due to the sheer size of the thing I eventually passed it on. I only have one poor photograph of the set, I will ask the current owner at the next Harpenden for some better pictures, ( He still owns all these ex college sets! ) .

Regards, Mick.

[Danny]

Hi
I have an Ekco and a Philips, both with busted tubes these sets must be restored.

I have had some signs of life out of the Ekco without the CRT connected, but haven't bothered with the Philips yet.

Here are some pics.
Note the Ekco cabinet can be stripped to gain access to the tube.

Thanks Danny

[Mikey405]

Hi everyone.

The old TV Museum down in Beaford in Devon has a Bush CVB100. A good friend of mine has the Murphy equivalent too.

From Mike.

[ppppenguin]

No round CRT CTV was sold to the UK public. When we started the UK colour service in 1967 rectangular tubes were well established. The classic CRT was the 25" Mullard A63-11X.

Substantial numbers of sets with round CRTs were sold in the US since their NTSC service started in 1954.

[FERNSEH]

There is an image of a round CRT colour TV set on the Radiofil Forum.

The set is a Philips TVC1

http://retro-forum.com/viewtopic.php?t=11051

DFWB.

[Trish]

I,m going to throw another one into the pile. This time it concerns a Professional monitor that was built with three round CRT's and dichroics + surface silvered mirrors to combine the images.

I actually got to play with one of these in the late sixties, along with a flying spot slide scanner that was six racks long and heaps of valves in it.

The monitor was designed and built in the UK (as was the slide scanner that came from the Mazda works that closed down) by Cinema-Television Limited which came out of the ashes of the Baird Television Company. The company is still going to this day as Cintel International Limited.

I do know that someone that used to work at Cintel knows of this monitor. At this present time I cannot for the life of me remember any information about where he is now, or any more details of this monitor.

Perhaps somewhere in the basement of the Science Museum one of these exists.

Trish

[dave walsh]

Any more info on why this was built Trish? Was it a US sub-contract or something else?
Just interested - sounds almost like a mid-thirties Baird
type development.

Dave

[Trish]

Originally Posted by dave walsh

Any more info on why this was built Trish?

I really don't know why or when it was built. The only thing I can tell you is that it was RGB input and when working the results were pretty stunning. It was a pig to get the three tubes lined up and converging correctly. It made doing a normal set look like childs play

Trish

[ppppenguin]

I once met an experimental triniscope colour monitor. ISTR it used 3x 14" rectangular CRTs in a huge frame with rather large dichroic filters. I arranged to get it out of the old and abandoned Thorn-EMI Research Labs building in about 1986 but I don't know what's happened to it since.

Before shadowmask tubes, the triniscope was the only practical direct view colour display. The Baird telechrome was not very practical and projectors are not direct view.

[Trish]

ppppenguin - The thing I played with was like that of course. But it did have round tubes.

Not wishing to cause this thread to go off track. But I do recall heading off to Rediffusion's (LWT) studios in Wembley. When they were moving out and walking away with a lot of kit. That was in the late Sixties and early Seventies. At that time I was at what was the Guildford Tech. Then I moved to the West Surrey College of Art. A lot of kit was really ancient. But a real challenge

I don't know where the kit all went. But for people here, it would be a treasure trove like no other if it could all be located.

Cheers,

Trish

[dave walsh]

Thanks for that response. I'm quite pleased re the "telechrome" ref as the Baird comment was only a guess on my part. There is a page on the web which includes the Radio Times saying that the picture resulting was "entirely natural" [1942] but then he died four years later. A few hundred yards away from here actually. It is something that I refer to a lot but then I find it strange to end up living near Baird's house after years of interest in TV. Was the early use of round CRT's due to the glass blowing or TV technology I wonder? Dave

[ppppenguin]

Originally Posted by dave walsh

Was the early use of round CRT's due to the glass blowing or TV technology

Glass blowing. Blowing a rectangular tube by traditional methods strikes me as almost impossible. It required mass production moulding processes to make it feasible. Also for any given form of construction a round tube can better withstand the immense air pressure, It doesn't have stress points at the corners.

The first shadowmask colour CRTs were developed when round CRTs were still dominant so it's not surprising they started as round. I really don't know why they stayed round even after monochrome tubes were almost universally rectangular.

[tubesrule]

I'm not sure if this is similar to the one Trish saw, but here is a picture of an RCA Triniscope from 1950. It used three 16" round crts aimed into the light box on the right side that housed the dichoric mirrors.

Darryl

[ppppenguin]

Darryl, that's a great picture! The one I saw was a generally similar shape (that may be inevitable if you are trying to arrange 3x CRTs) but with a metal frame and 14" rectangular CRTs.

[tubesrule]

I got to crawl around this one a couple of years back. It is very "lab prototype" in construction. Nothing is finished off, and even the cabinet is just spray painted plywood. Definitely for concept approval (or disapproval) only.

Darryl

[tubesrule]

I was just poking my nose around to see how it was constructed. I did notice that many cables seemed to be unplugged, although everything appeared to be intact. I assume it could be made operational, but it is my understanding that these were not NTSC compatible sets, so you would either have to drive it directly with RGB or come up with an appropriate encoder.
Here's a picture of the front.

Darryl

[ppppenguin]

I would assume RGB. It might have been made before NTSC was finalised. Even if it's later, RGB would have been more useful in the lab and the NTSC>RGB decoder might well have been another hefty crate of stuff.