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Old 13th Jan 2004, 9:19 am   #41
oldeurope
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Default Re: Favourite Colour tv's

There is no curve on the inside at so called real flat
CRT's. In modern sets the katodes are in line, so
no electrical convergenz is neccesary. Of course you
can adjust convergenz with magnets. I have no
favorite color TV, but I don't like the 100Hz picture.
Digital picture is good, but only if nothing moves.
It is a bad thing that they pick up digital pictures
for analog transmitters.
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Old 13th Jan 2004, 9:54 am   #42
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Default Re: Favourite Colour tv's

Is the inside of a flat screen curved or not. There's only one way to find out for sure. Break one open and take a look If it really is flat inside and out then that's some pretty impressive tough glassware to stand the pressure. It's about 2 tons for a 28 " 16:9 tube.
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Old 13th Jan 2004, 12:49 pm   #43
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Default Re: Favourite Colour tv's

I guarantee that the inside of the flat CRT is curved. At least the ones that LG Philips make are. I work on many new sets for a major manufacturer and if the back is removed you can see into the side of the CRT where the faceplate joins the flare. There IS a curve. I cannot speak for Trinitron...perhaps they use a different method. The curve is not very pronounced but it IS there.

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Old 14th Jan 2004, 9:06 pm   #44
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Default Re: Favourite Colour tv's

As far as I am aware all large screen (28 " & above) flat CRTs have a curve on the inside of the glass. The curve is most pronounced (or solely) in the X-axis. The result is that the glass is thicker at the outer edges of the picture.

If you view a plane white screen from a pattern generator on these CRTs, you will notice that the picture is slightly darker at the edges. This is because the light has had to travel though more glass than at the centre of the screen. One of Toshiba's top of the range sets modulates the video with a line rate parabola to cancel this shading effect.

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Old 17th Jan 2004, 2:15 am   #45
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Default Re: Favourite Colour tv's

Replying to a few points raised by Jon. I have noticed with a most of the new LCD screens that like the LCD monitors you have to be sitting at the corect angle to get the best display, one up for the crt here then.
Moving on to the Sony trinitron tube, Yes they are bright but always look concaved and have a strange lensy effect to them. They are all the same from the original to the very latest wega things.
Your 1967 19 " Pye tv like my 1972 20 " ITT/KB mono tv both have flattish 110 degree crts. The truth is they ironed out most of the problems with large screen mono tubes by the 60's and with the use of more powerfull timebase valves such as the PL504, PY88 DY802 and the PCL805 these older sets could produce some very good pictures. Along came colour and it was back to 90 degee deflection as it is today. The reasons are down to power (it takes a lot more of it to deflect beam 110 degrees than 90 degrees) and also for convergance and purity reasons.Some of of the continental sets and later sets such as the TX10 did use 110 degree tubes which worked rather well but most makes went back to good old 90 degrees for reasons of power saving and picture quality.Basically 90 degree tubes are more efficient and need less correction ccts to eliminate errors and distortion on the edges of the picture. But as I said earliar there is a new generation of super slim crt's about to be released by LG Philips.
Cabinet colours, ****** awful and have been since the 1980's. They went to black plastic in the mid 80's, then to charcoal and finally to this silvery grey in more recent years which we are still afficted with today. :
Finally vintage set usage. I used my Decca Bradford as my No1 set right up until 1996 when I lived in my bedsit. There were a few breakdowns but I was always able to clear the faults and have got loads of spares. This set is now in my workshop and gets used several times a week. I am happy about this as the main set in the lounge gets a real battering and can be on from the early hours when the kiddies progs start to the early hours of next day with me watching BBC News 24. For heavy use like this I do not think it is fair to expect a vintage colour set to be used, after all back in the 1970's most sets were only on for a few hours each evening, because most people back then had a life and did not suffer the joys of daytime tv that we have to . The other older tv's that I use on a regular basis are both mono and in my workshop. The first is the hybrid single standard (625) ITT/KB VC205 which I mentioned earliar and my trusty old 12 " batt/mains BRC1590. Both have very good tubes and produce brilliant pictures. Both date from 1972. From 1969 I have a 19 " mono RBM A640 duel standard. Although it needs some attention I still watch it several times a week.
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Old 21st Jan 2004, 1:21 am   #46
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Default Re: Favourite Colour tv's

As we have covered the first generation single standard (625) colour tv's what about the original duel standard colour sets. Personally when I started work in 1976 most of these first generation sets had gone to the big graveyard in the sky. I did get to see and work on a few Decca CTV25's with their prestomatic tuner. They still gave great pictures and were not to bad to work on. Apart from one Bush and a few Dynatron duel standard colour sets which I saw working thats it.
Does anybody out there remember working on or owning one of these early monsters. They must have been quite daunting to many engineers when they came out new in 1967. There is one set that I never ever saw and that is the elusive ITT/KB CVC1&2. Apparently it was fully handwired but apparently was reasonably reliable with a good picture and like the later CVC5 was light on its tube. Is this true. It must have been a nightmare to work on.
So are any of these 1st generation colour sets anybodys favourites or are they best forgotton.
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Old 21st Jan 2004, 9:49 am   #47
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Default Re: Favourite Colour tv's

Yeah - worked on all of these! Plus:
GEC - much like s/std
Philips G6 - better than later s/std one
Baird 700 - lovely - weird circuitry
BRC2000 - excellent build quality and picture

The Bush CTV25 suffered from incineating LOPTx, and that 100 ohm 1 watt feeding line pulses to burst gate.
Pye was as bad as s/std one
GEC had usual awful double sided print
CVC1 and CVC2 beautifully made and reliable

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Old 1st Feb 2004, 2:34 am   #48
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Default Re: Favourite Colour tv's

Thanks Mike
I have always admired the ITT/KB tv's from there mono duel standards right up to there cvc 30 series. I would imagine the CVC1&2 looked like a larger version of the VC53 duel standard mono but bigger of course. Did it use pcb sub boards or was it straight metal chassis job?
As the subject of Favourite colour tv's has been favouribly received I wonder if a topic of Favourite mono tv's would go down well.We could include early 405 liners up to the last hybrid 625 single standard sets.
All responses welcome.
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Old 1st Feb 2004, 10:50 am   #49
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Default Re: Favourite Colour tv's

Simon
Memory a bit faded, but IIRC, CVC1 and 2 were totally wired - no PCBs.
Yes, we must start a thread about monos.
Another thought was a thread of stock faults on early colour sets? Comment, everyone, please

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Old 11th Feb 2004, 10:46 pm   #50
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Iwould put it the other way round ITT K/B CVC5/8 1st Decca Bradford 2nd.My CVC5 Works every evening as it has for 33years Fantastic ! Far better picture than any mordern set
 
Old 15th Feb 2004, 9:49 pm   #51
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Wow a CVC5 running as the main set with a good picture still, I like it. Just proves what a superb set they were. Back in 1977 I wanted to buy the ITT/KB CVC5 but could not afford one as ex rental ones were still going for between 120-150 whilst my other favourite the Bradford were being sold off for as little as 50. This was still a lot of money for a trainee engineer though.
New thread on stock faults is a possibility, do we include mono sets as well?
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Old 16th Feb 2004, 9:37 am   #52
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Default Re: Favourite Colour tv's

Hi Simon
Yes - think we should. Should it go in the 'Tips' section?
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Old 16th Feb 2004, 10:12 pm   #53
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Default Re: Favourite Colour tv's

Probably best here in the TV section - it's the first place vintage TV enthusiasts would think to look.
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Old 16th Feb 2004, 10:45 pm   #54
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Default Re: Favourite Colour tv's

It has been suggested that we should open up a tv stock fault forum so consider it open.
Someone somewhere was asking about a favoutite vcr forum. But as I have got no strong feelings for these beasties I will let someone else open one, and wish them well
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Old 27th Sep 2004, 8:10 am   #55
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The only really awkward thing about the CVC1/2's was trying to identify the hand wired components underneath the chassis from the service manual. Otherwise, fantastic pictures, very reliable, easy on tubes and IMHO, the CVC1 was the nicest looking of all first generation colour sets. If you'll excuse my self-indulgence , there's a picture of a KB CVC1 at: www.oldtechnology.net/kbcvc1.jpg

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Old 27th Sep 2004, 8:44 pm   #56
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Default Re: Favourite Colour tv's

anyone remember the teleton hybrids with the feed resistors mounted on the main smoothing block metal cabinets and if you left a plastic spacer out it got interesting.
also a french monster solid state with thyristors in a bridge arangement i cant remember the make but thay chomped tubes but were ultra reliable.
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Old 27th Sep 2004, 9:38 pm   #57
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Wow I did not expect to see this topic back. I thought it was killed or moderated off a long while back
Teletons? I have very vague memories of these. We did not see to many of them. They did use some strange valves though. I think they were from the far east somewhere, possibly even Japaneese.
We did not see to many French sets here in the UK. As for Thyristers, ok in power supplies but not very clever idea to use them in line output stages. I dreaded those Grundigs, Kortings and Finlox peacock sets.
I must admitt to being very happy about seeing thyrister line output stages consigned to history or better still total obscurity
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Old 28th Sep 2004, 7:22 am   #58
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I think those Teletons used weird kind of simple PAL using a higher and lower frequency than the normal 4.43 and then doing something bizzare with it didn't they? Or was that later Teletons? I recall that there were 2 20 " Teletons which looked absolutely identical with 4 touch buttons on the bottom right but one was hybrid and the other solid-state. The hybrid set always suffered from frame linearity problems and a slightly wishy-washy picture but the solid state sets were fairly reliable and gave a pretty good picture even though they were still simple PAL.
 
Old 28th Sep 2004, 9:18 am   #59
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Default Re: Favourite Colour tv's

Interesting stuff! Always thought the Grundig 5010/6010 were excellent sets - the thyristor LOP stages did not give much trouble. The main problem was that engineers did not understand how they worked. But there again, some struggled with figuring out a PL81/PY81


Only worked on the hybrid Kortings - again, excellent sets, and very reliable. They used a ladder-network RC oscillator for ident, locked to the burst-derived 7.8khz.
Teleton - I remember the hybrids with the weird valves, and touch buttons that were oscillators that stopped when you touched the buttons, unlike the Grundig that amplified the mains hum from your finger.

Only French sets we saw were Emo, with EL509 and EY500.
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Old 28th Sep 2004, 10:10 am   #60
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Default Re: Favourite Colour tv's

Ah yes, Teleton. I only ever fixed one of these, and that was enough. I remember it had valves, but whether it was hybrid I can't recall. It was obviously designed on the 'replace one' methodology (remove parts until it stops working, then put the last one back). : It was simple PAL, and had AC coupling on the luma and the colour difference signals - no clamps to be seen. The effect on News at Ten was interesting, with the newsreader's face changing colour every time the inset picture changed. The CRT also had low focus voltage (i.e. <= grid 2 voltage) just like a mono tube, and had weird Japanese phosphors so reds were orange.

Surely the worst colour TV ever to be marketed in the UK - unless anyone can beat it...
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