1st generation UK colour TV?

[Combwork]

Back in the 1970's my wife and I had a small workshop repairing antique musical boxes. The landlord was OK with this as long as I put up some kind of shop display to keep in line with other shops on the street. I've always had an interest in (but no technical knowledge of) old radios so I started to buy them, very cheap. I had an arrangement with traders at the local market that for a minimum payment of £2, I would buy absolutely any radio they brought to me. This guaranteed that I'd not only get the trash, but also anything decent that came their way. Then I got a 'phone call from a local TV shop that refurbished old TVs they'd taken in part exchange. They'd just taken in a huge colour set in a polished wood cabinet and decided they'd rather not get involved, so I got it. Turned out to be a DECCA CTV25; one of the first batch of production colour TV's in the U.K. In 1966 it cost about £600 ($1200); not much less than a small family car.

Question? It had transistor audio but valve (tube) video including a valve driven EHT supply. Took about 3 minutes to warm up before the picture appeared but provided the convergence and focus were set up properly, it had one of the best pictures I can remember seeing. The EHT supply was hidden inside a 12" high metal box with a radiation hazard symbol on the front along with the warning "Do not operate with this cover removed". Was this serious, or was it just to keep meddling fingers out of something that could kill?

The set had push-button tuning and a nasty habit of arcing when the channel was changed. I was told this was due to a momentery spike in the EHT supply as the brightness dipped. This only happened when my wife was watching it on her own; once when I was out she claims it arced, smoked and she saw flames so she unplugged it and threw a plantpot full if sand into the back. Although incredibly it still worked after this, she made it clear that that f****** fire hazard had to go. Fair enough, now it's in a museum.

[N9ZQA]

The shunt regulators for high voltage in television sets (6BK4 comes to mind) were capable of producing X-rays under certain operating conditions. I wouldn't imagine that they'd be as powerful as say a medical X-ray unit, but it probably wouldn't be prudent to spend an extended amount of time near an open HV cage while troubleshooting.

See http://www.time.com/time/magazine/ar...837185,00.html for one particular case involving GE sets.

-Jim

[steerpike2]

Originally Posted by Combwork

Turned out to be a DECCA CTV25; one of the first batch of production colour TV's in the U.K. one of the first batch of production colour TV's in the U.K. In 1966 it cost

So is then a dual standard set, 405 line + pal ?

I wish there were some valve sets around here - but since TV sets only went on sale in 1975 - and only locally made ones allowed, the 'antiques' are all solid state. Very boring.

[Combwork]

[QUOTE=steerpike2;2849182]So is then a dual standard set, 405 line + pal ?

I wish there were some valve sets around here - but since TV sets only went on sale in 1975 - and only locally made ones allowed, the 'antiques' are all solid state. Very boring.[/QUOTE]

Band 1 UHF 625 lines, band 3 VHF 405 line and band 3A. Not sure what that was; before I got the set the standard change switch had been disabled making it 625 line UHF only. It's possible 3A might have been for 405 line colour; the commercial companies were pushing for this but the government insisted colour should be on 625 UHF only.