TV theory

[toshiba tony]

Hello,
Can anyone suggest any available books on tv theory. My main interest is benefits and drawbacks of CDA over RGB modulation in colour tv. I always seem to remember that sets with CDA, such as the G6 gave far better pictures.
I'm getting older now and the grey matter is getting eroded. I officially left the tv trade last month i threw all my books out a few years ago. I'm sorry I did.

[Nuvistor]

Try the local library for " Colour TV Theory" by G H Hutson published 1971, probably need to order it. It's a UK book.

If you want a download of another book try the RCA home study course, NTSC but good information.
http://www.americanradiohistory.com/...ourse-1966.pdf

Lots more available.

[toshiba tony]

Thanks Frank

[Nuvistor]

CDA v RGB. Later RGB sets produced excellent pictures but I agree some early RGB designs did not seem too good. The only one I can comment on was the RBM A823 chassis, the picture was nothing like as good as the Pye 691 range, on the other hand the RBM dual standard CTV25 with CDA drive was not that good again compared to the dual standard Pye.

The first dual standard Baird with the high level demodulation gave excellent pictures, I would need to check but I think that was Y to cathode and colour to grids.

RGB drive is capable of excellent pictures, I can only put the failures down to the design of those sets.

[toshiba tony]

Thanks for your interest. What was peculiar about Finlux peacocks. if the tube wasn't flat I seem to remember they were belters. I recall they were grid modulated, were all cda circuits driven on the grids, and the cathodes strapped? I need to refresh. I now have a form of dementia so anything that occupies my mind is good, Cheers.

[Nuvistor]

The Hutson book is available as a download from
https://ia800701.us.archive.org/2/it...sionTheory.pdf

I will try to find others, there was one that was the definitive book but I cannot recall the title or author, it was mainly NTSC but that does not matter, PAL is just a modification.

[Nuvistor]

Has far as I know CDA presented R-Y, B-Y and G-Y to the grids while the Y signal was fed to the three cathodes, the levels of the Y signal was variable for each cathode.

I did not see CDA used in a different way than that.

Never saw a Finlux CTV.

Edit. Two sites if you want some reading.
http://www.americanradiohistory.com

http://www.earlytelevision.org/color.html

[Nuvistor]

This is an early CTV theory book, 1955, there are various circuits but one is an RGB drive circuit where the signals are fed to the grids of the CRT not the cathodes has was usual in the sets i repaired in the 1970's.
http://www.americanradiohistory.com/...Kiver-1955.pdf

[Welsh Anorak]

Hi
I've always thought that the CDA drive resulted in a more natural colour, The G6 in my opinion gave the best picture of all the duals, and used a PFL200 (with all its problems) as luminance drive just like the Baird. I think that valves were happier with CDA drive. The Tandberg and the Skantic/Luxor possibly used valved RGB drives, but I might be wrong.
As said above, it comes down to design. The GEC 2028, Pye dual standard, the Decca CTV25 and the Bush CTV25 used their own take on the Mullard circuits and produced results that were good to poor in that order. Bush then produced the oddball CTV174 that was half-way between the CTV25 and A823 with transistor RGB drive and produced a better picture than either.
Of course for true overkill there was the B&O 2600 with three ECL84s, another for blanking, the 12HG7 as luminance output and three EAA91s as bi-directional clamps. Add the separate EHT and line output stages and you had a fearsome beast - and an efficient room heater.
Glyn
PS Did see a couple of Finlux peacocks but I was so busy tearing my hair out trying to get the damn things to work that I failed to notice the good pictures.

[toshiba tony]

Must admit, I didn't like thyristor line stages. And the Ipsalo circuit did my head in. Scantic, Saba, Grundig and others. Good sellers but when they broke down.
&^%$*&*((*&^

[Nuvistor]

I repaired the occasional Grundig but did not have the pleasure of fixing those other makes you mention. Anyway I am sure you just said "oh dear, one of these" and then fixed it.