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Pye 405 line CTV.

 
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Pye 405 line CTV.

Post by Till Eulenspiegel » Tue Jan 05, 2016 7:03 pm

Let's find out if that frame linearity fault can be fixed once and for all. Just about everything in the frame timebase has been checked except one component, the scanning coils. Along with the original metal cone CRT which went down to air many years ago, the scanning coils were supplied by RCA. After removing the CRT neck components and the metal screen which is fitted at the rear of the scan coils I noticed a fair amount of corrosion on the tags which connect to the coil lead out wires. You never know, I might get lucky and the frame linearity fault could just be bad solder connections.
These early colour CRTs have a 50mm neck. I'm also on the lookout for a replacement CRT socket.

Till Eulenspiegel.
Attachments
PyeCTV_0217.jpg

 
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Re: Pye 405 line CTV.

Post by Bobhowe » Tue Jan 05, 2016 8:20 pm

Hi David could this be this years contender for the queens speech ? Would HKS not have a tube socket for it regards Bob

 
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Re: Pye 405 line CTV.

Post by Till Eulenspiegel » Tue Jan 05, 2016 8:53 pm

Hi Bob,
Ready the set for the Queen's Speech? That's a good idea. We know the set works, in a fashion, but since the set has been in my possession (it was acquired by me in 2001) I've never come up with an answer to the frame timebase problem.
Later this year the Pye colour set will be sixty years old.

Till Eulenspiegel.

 
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Re: Pye 405 line CTV.

Post by Bobhowe » Tue Jan 05, 2016 9:20 pm

Hi David do you think there should be a forum vote on it to get it ready for its 60th Birthday as well as this set is very special

 
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Re: Pye 405 line CTV.

Post by Till Eulenspiegel » Tue Jan 05, 2016 10:27 pm

Hi Bob,
I have another early colour set coming up for restoration. This one is a dual standard hybrid. The Pye is with the exception of a few crystal diodes all valve. Not a transistor in sight.
So what's to be, the Pye or the mystery newcomer?

Till Eulenspiegel.

 
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Re: Pye 405 line CTV.

Post by Bobhowe » Tue Jan 05, 2016 11:00 pm

Hi David i will start a new thread & let the forum decide

 
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Re: Pye 405 line CTV.

Post by Till Eulenspiegel » Tue Jan 05, 2016 11:14 pm

Democracy in action.

Till Eulenspiegel.

 
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Re: Pye 405 line CTV.

Post by Till Eulenspiegel » Tue Jan 05, 2016 11:32 pm

Bobhowe wrote: Would HKS not have a tube socket for it regards Bob


I've tried searching ebay without any success. Didn't some scope tubes use this base?

Till Eulenspiegel.

 
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Re: Pye 405 line CTV.

Post by TVJON74 » Tue Jan 05, 2016 11:40 pm

Hi Till,
What type of socket is it and what's the tube?

 
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Re: Pye 405 line CTV.

Post by Bobhowe » Tue Jan 05, 2016 11:51 pm

Yes you are right i t could be a scope base Ed Dinning might have one

 
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Re: Pye 405 line CTV.

Post by Till Eulenspiegel » Wed Jan 06, 2016 1:11 am

Hi Bob, I'll have a word with Ed about the tube base.

Hi Jon, The CRT presently installed in the Pye is a Mullard AX53-10, it's an all glass round faceplate tube and is similar to the American 21CYP22.
The original CRT was the RCA 21AXP22 which is a metal cone type. This tube has gone down to air as most of these metal-glass tubes do.
The AX53-10 was made by Philips in Holland. Used in the Philips K4 CTV.

Till Eulenspiegel.

 
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Re: Pye 405 line CTV.

Post by ntscuser » Wed Jan 06, 2016 2:02 am

I believe the Philips roundie has a brown tube base whereas the RCA one is black?

 
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Re: Pye 405 line CTV.

Post by Till Eulenspiegel » Wed Jan 06, 2016 2:07 am

That's correct. That's how the tubes I have here are like.

Till Eulenspiegel.

 
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Re: Pye 405 line CTV.

Post by Doz » Wed Jan 06, 2016 10:31 pm

That tube base looks familiar ... :aaq

20160106_212238web.jpg

20160106_212322web.jpg

20160106_212311web.jpg


It's from my homebrew monitor with DG7-32 CRT http://andydoz.blogspot.com/2014/09/simple-tv-using-dg7-32-scope-tube.html

I got the base from eBay seller "Michael's elctronics emporium" if memory serves.

 
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Re: Pye 405 line CTV.

Post by Rebel Rafter » Wed Jan 06, 2016 11:36 pm

Hi from RR. What a revelation this is, I never knew there were 405 colour sets made, I thought colour was never used on 405, only tried out experimentally. Didn't colour not start in the UK until 1967? How come there was CTV's here in the 1950's? or were these sets made for export to the states, I know they had colour in the 50's, but they didn't have 405, did they? or did they? or were these made for Europe? I thought the US always had 525 lines. What colour system were these PYE sets made for? The power consumption must've been phenomenal with a 50mm neck and all valves and I thought the B&O 3400 was high on power at 360w. How much power did these sets use? RR.

 
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Re: Pye 405 line CTV.

Post by Terrykc » Thu Jan 07, 2016 12:02 am

The first demonstration of colour that I can recall was at the Earls Court Radio Show.

I can't remember the year but it was well before we had any 625-line transmissions in this country.

I was 14 when I went to the Radio Show for the first time - that would have been in 1958 - but I'm sure it was later than that. However it would have been before the Pilkington Committee decided in favour of 625-lines as the future UK system and quashed any ideas of colour on 405-lines. That was in June 1962 so I'm guessing that the demonstration was around 1960.

It was in a special gallery and featured sets from all the manufacturers side by side so that visitors could walk past this continuous stream of colour sets.

One of them, I recall, was looking decidedly sick. I think it was the GEC set but apologies if I've made a mistake!

The demo consisted of a continuous sequence of slides and test films - the same ones that were shown in the colour test transmissions on BBC-TV* - on 405-lines, of course! - from Crystal Palace every afternoon in lieu of the test card.

* Note that it didn't become BBC1 until BBC2 started in 1964!

 
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Re: Pye 405 line CTV.

Post by Cathovisor » Thu Jan 07, 2016 12:28 am

You may find the colour segment here (at 1:03:10) of interest. The film is This Is The BBC, which won the BAFTA for Best Specialised Film of 1959.

The system used in these experiments was a variation of the NTSC system.

 
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Re: Pye 405 line CTV.

Post by ntscuser » Thu Jan 07, 2016 5:22 am

The 405-line colour TVs were built for evaluation purposes only, none were marketed. The trade feared that if the consumer thought that colour was "right around the corner" sales of B&W sets would dry up. For that reason there was very little mention of the subject in the trade press at the time.

The Pye is extremely rare in not having been adapted to 625-line PAL colour operation at some time in the 1960s as almost all the other surviving colour sets were.

 
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Re: Pye 405 line CTV.

Post by Terrykc » Thu Jan 07, 2016 11:04 am

Cathovisor wrote:You may find the colour segment here (at 1:03:10) of interest. The film is This Is The BBC, which won the BAFTA for Best Specialised Film of 1959.

The system used in these experiments was a variation of the NTSC system.
It's a pity that the APTS couldn't get the aspect ratio right! It looks as if it has been cropped to 16:9 and then shown at 4:3.

By "variation" I presume you mean 'adapted for the 405-line system'.

 
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Re: Pye 405 line CTV.

Post by Cathovisor » Thu Jan 07, 2016 12:08 pm

Terrykc wrote:
Cathovisor wrote:You may find the colour segment here (at 1:03:10) of interest. The film is This Is The BBC, which won the BAFTA for Best Specialised Film of 1959.

The system used in these experiments was a variation of the NTSC system.
It's a pity that the APTS couldn't get the aspect ratio right! It looks as if it has been cropped to 16:9 and then shown at 4:3.

Unfortunately, very common with 4:3 material on YouTube but I'm not sure where the error creeps in - it looks like it's been double-ARC'ed. This is correct in terms of aspect ratio but seems to have very low level sound.

Terrykc wrote:By "variation" I presume you mean 'adapted for the 405-line system'.

Isn't that what a variation is? A change or slight difference? A different or distinct form or version of something? Mere semantics.

 
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Re: Pye 405 line CTV.

Post by Till Eulenspiegel » Thu Jan 07, 2016 12:41 pm

Other 405 line colour receivers such as the GEC TT4 have a very prototype look about them. The Pye which are discussing is quite different, it's got the appearance of a series production set. A fair amount of investment must have gone in to making it. Perhaps they had the North American market in mind?
The colour sub-cattier frequency was finalised as 2,657,812.5 Hz. That's the line frequency fH X 525 divided by 2
Apart from three special valves which were imported from America, two 6BY6 and a 6BD4 the others are the common Mullard types.
Two parallel PL36 and two parallel PY81s are used for the extra power requirement from the line output stage. Three DY86 diodes are employed for the EHT. The circuit arrangement is not a voltage doubler. The line output transformer has a 17KV winding. This along with the 6KV pulse present at the anodes of the two PL36 produces the 23KV for the CRT. The focus voltage comes from the 6KV source. The HT supply for the line output stage comes from a voltage doubler employing two flat selenium rectifiers. These have been replaced with silicon diodes.
About 1960 Ekco made an impressive looking 405 line colour set. The only known example has been converted to 625PAL. The set looks like a enlarged model T330.
I often hear rumours of other 405 line colour TVs. We should track them down.

Till Eulenspiegel.

 
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Re: Pye 405 line CTV.

Post by nuvistor » Thu Jan 07, 2016 2:00 pm

See page 17 for the USA NTSC specification and page 27 for the modifications required for a 405 system.
http://www.earlytelevision.org/pdf/Marc ... slides.pdf

Frank

 
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Re: Pye 405 line CTV.

Post by Till Eulenspiegel » Thu Jan 07, 2016 9:49 pm

Doz wrote:That tube base looks familiar ... :aaq


It's from my homebrew monitor with DG7-32 CRT http://andydoz.blogspot.com/2014/09/simple-tv-using-dg7-32-scope-tube.html

I got the base from eBay seller "Michael's elctronics emporium" if memory serves.


The colour CRT base on the 21AXP22 has fourteen pins, the same number as later tubes such as the A63-11X.

Till Eulenspiegel.

 
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Re: Pye 405 line CTV.

Post by peter scott » Fri Jan 08, 2016 8:07 pm

Terrykc wrote:The system used in these experiments was a variation of the NTSC system.
It's a pity that the APTS couldn't get the aspect ratio right! It looks as if it has been cropped to 16:9 and then shown at 4:3.
[/quote]

It would be interesting to know what is going wrong here. If you present YouTube with 4:3 material they do appear to present it more of less correctly but the BBC appear to be making a similar mess of 4:3 in recent times:
http://www.vintage-radio.net/forum/show ... p?t=122305

Peter

 
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Re: Pye 405 line CTV.

Post by peter scott » Fri Jan 08, 2016 8:08 pm

Terrykc wrote:It's a pity that the APTS couldn't get the aspect ratio right! It looks as if it has been cropped to 16:9 and then shown at 4:3.


It would be interesting to know what is going wrong here. If you present YouTube with 4:3 material they do appear to present it more of less correctly but the BBC appear to be making a similar mess of 4:3 in recent times:
http://www.vintage-radio.net/forum/show ... p?t=122305

Peter
Last edited by Cathovisor on Fri Jan 08, 2016 8:11 pm, edited 1 time in total.
Reason: Fixed quotes.

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