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Old 15th Feb 2019, 11:31 pm   #61
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Default Re: Types of CRT used in colour TV's.

Talking of fiddling with sets, my Grandad used to get bored & fiddle with the controls on his TV then try to get them back to normal.

At least once he couldn't manage it & my Dad had to sort it out.
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Old 15th Feb 2019, 11:33 pm   #62
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by Philips210 View Post
Another good article, this time on the then newly developed PIL CRT can be found in the June 1973 issue of TELEVISION magazine available here https://www.americanradiohistory.com...UK-1973-06.pdf
Thank you for the link, much more reading for me to do, same as the other link!

Thanks
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Old 15th Feb 2019, 11:47 pm   #63
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by InsertNameHere View Post

Doesnt a certain degree deflection give x-rays when set up in a certain way?

Do different degrees give a different picture quality, or give any improvements other than size difference?

Why didnt colour sets start with 110 degree deflection CRTs if they already existed?

Thanks
Hi.

I am not sure whether the deflection angle has much significance regarding X-rays. The front face plate is necessarily thick for structural reasons but is also leaded glass which absorbs X-rays. If the CRT is operated within spec, then no significant X-rays will be produced. If the EHT is excessive then X-rays are more likely to be present around the cone at the back of the CRT.

110 degree CRTs need greater scanning power to deflect the electron beams compared to 90 degree types. They also need more raster correction especially early types. In general, the sharpness of the picture in 110 degree CRTs is not on par with 90 degree types.

I think the reason for the first generation deltas being 90 degree is possibly due to the availability of suitable line output valves. The PL509 was intended for 90 degree sets and wouldn't have coped with the scanning currents demanded by a 110 degree CRT. The early 110 degree deltas used a PL519 line output valve. East-West raster correction would need to be applied to a 110 degree CRT adding further complication. Starting out with a 90 degree delta made life easier at least and the picture quality was in the main very good. There may have been many other reasons, perhaps others might like to comment on this point.

Also, in general, we didn't see many 110 degree deltas in the UK. Most of these would have been continental sets such as the Grundig 5012 and Telefunken 711. The British Philips G9 chassis used a 26" 110 degree CRT. I think there was also the Thorn 4000 series that had a 110 degree CRT.

Regards,
Symon.
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Old 15th Feb 2019, 11:51 pm   #64
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Default Re: Types of CRT used in colour TV's.

If you haven't already seen it, watch this programme, from a daytime series produced by Channel 4.

Probably up your street!

https://www.youtube.com/watch?v=QEi1ggtO5Oc

PS the youtuber who posted it says it's from 1988, but I started work in 1989 and remember recording it off air on a ferguson 3V23 that was given to me by a guy I met at work. The credits date the series at 1989, and I think it was first broadcast in 1990.
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Old 16th Feb 2019, 12:03 am   #65
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by Philips210 View Post
I think there was also the Thorn 4000 series that had a 110 degree CRT.
Hi Symon,
I always thought the 4000 had a PIL tube? I did have one for a short while when I was a lad- it had rather sickly colour as the tube was not great. I never saw another 4000 then and I've never seen one since! I seem to recall an article in 'Television' about them.

Also was the 8000 series a delta or PIL?

Cheers
Nick
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Old 16th Feb 2019, 12:13 am   #66
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by slidertogrid View Post
This is a very interesting thread with lots of interesting information!
It seems there are some posts missing from the start though as the first post starts with a quote and there are no pictures of what is being discussed but there is a reference to how good "the tube " is?
Has it been split from another thread for some reason? If so can anyone direct me to the original thread please? As it is this thread seems to start a bit disjointed....
Hi Rich,
Indeed this has been split from this https://www.vintage-radio.net/forum/...&page=12thread in the TV & video section. Starts from post 224.

Hope that helps
Cheers
Nick
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Old 16th Feb 2019, 12:19 am   #67
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Default Re: Types of CRT used in colour TV's.

Hi Nick.

The 4000 used a delta gun CRT. There was a servicing article in TELEVISION, March 1981 https://www.americanradiohistory.com...UK-1981-03.pdf


The 2000, 3000, 3500, 4000, 8000, 8000A, 8500, 8800 and 9800 all used delta gun CRTs.

The 9000 (90 Deg) and 9600 (110 deg) used PIL CRTs

Regards,
Symon
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Old 16th Feb 2019, 12:38 am   #68
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by 1100 man View Post
Also was the 8000 series a delta or PIL?
The 8000 and 8500 were both delta gun the 9000 was one of the first PIL chassis along with the ITT CVC20, these sets used an RCA designed PIL tube with a bonded (Toroidal?) Yoke that was glued to the tube.
The occasional set of coils became unbonded but with care they could be re glued and reset fairly easily.
Thorn had a habit of mounting the delta gun tubes upside down to help mask the lack of raster correction the problem with this was that the nicotine infused condensation tended to run down to the anode cap and cause arcing , I lot of houses had no central heating back then so the sets were turned on for an evenings viewing in a cold un heated front room .

Delta gun tubes continued to be used by some manufacturers in budget models after the PIL and 110 degree tubes were in production. The Pye 725 (90 degree simplified version of the 731) and Thorn 8800 (22" version of the 8500) spring to mind..
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Old 16th Feb 2019, 12:52 am   #69
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Default Re: Types of CRT used in colour TV's.

Well well, thank you both for the information:- most informative!
I was once very familiar with the 9000 with it's PIL tube with bonded coils. I just assumed that all the other 9xxx series would be PIL! The 9000 was capable of excellent pictures if the tube was good.

Cheers
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Old 16th Feb 2019, 12:54 am   #70
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Default Re: Types of CRT used in colour TV's.

Hi.

There was also the thoroughly modern Toshiba RIS inline gun CRT as used with the RRI Z718 chassis. This was an 18" CRT though there was also a 22" version but can't recall if it was a Toshiba CRT.

The Decca 80 series and Rediffusion Mk3 are other early examples of the inline gun CRT being employed.

Thinking back, the RRI Z179 used a 110 degree delta CRT (26") I think.

Regards,
Symon
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Old 16th Feb 2019, 3:03 am   #71
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by Philips210 View Post
I am not sure whether the deflection angle has much significance regarding X-rays. The front face plate is necessarily thick for structural reasons but is also leaded glass which absorbs X-rays. If the CRT is operated within spec, then no significant X-rays will be produced. If the EHT is excessive then X-rays are more likely to be present around the cone at the back of the CRT.
Hi

What causes the x-rays? Is it the EHT?

Understandable that 90 degrees were still being used, i’d imagine they were more universable with sets and parts? Easier to set up, too i’d guess?

Were 110 degree PILs more common? Perhaps as the technology advanced for both, it would’ve been better to combine to two to make a better CRT design l together?

Thanks
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Old 16th Feb 2019, 3:08 am   #72
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by McMurdo View Post
If you haven't already seen it, watch this programme, from a daytime series produced by Channel 4.
I havent seen it before, i had a quick look at the title to see. I’ll watch it a little later as i don’t have sound at the moment.

It looks like its something i’d watch

Could have been a remastered version or just a re-aired version of a ‘88 showing in ‘90?

Thanks
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Old 16th Feb 2019, 3:09 am   #73
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Default Re: Types of CRT used in colour TV's.

Once 110 degree tubes came out the manufacturers advertised there more compact sets because they were shorter making the cabinet depth less.
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Old 16th Feb 2019, 3:56 am   #74
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Default Re: Types of CRT used in colour TV's.

Were 110 degree sets used into the 2000s?

My nan still has a CRT set from the 2000s as a back up but it’s just as deep as my late 70s set, i’ve tried looking through the ventilation holes to have a look inside but i couldn’t barely see anything.

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Old 16th Feb 2019, 7:13 am   #75
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Default Re: Types of CRT used in colour TV's.

I came out of the trade in late 2000 so I have no experience of what was fitted to the really late widescreen CRT era sets. Judging from what I have heard about the problems with the premature failure of Philips tubes it seems I got out just in time!

From what I can remember most small screen (20" and below) used PIL. Larger sets used 110 degree tubes 20 AX - 30 AX - 45 AX . There were exceptions, Sony tubes for instance. Some of their large sets were extremely deep and heavy.

In the late 1970's There was a 20" 20AX produced, used in the G11 with an offset final anode connection. I can't think of another set that used it. Meanwhile 20" KT3s were PIL as was the TX9 and similar age Panasonic sets.


Rich.
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Old 16th Feb 2019, 11:42 am   #76
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Default Re: Types of CRT used in colour TV's.

Hi All go to https://www.vintage-radio.net/forum/...ighlight=ctc15

This is a RCA Color Roundie with a Bad Cataract problem!
The tube neck is 2in diameter!
Keith
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Old 16th Feb 2019, 3:13 pm   #77
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Default Re: Types of CRT used in colour TV's.

@slidertogrid: I'm not sure that every narrow neck tube is a PIL tube. KT3 tubes were originally based on a Japanese design (Matsushita I think), but it may not have been PIL tubes depending on their construction.

I know that Videocolor and probably Standard Elektrik Lorenz used PIL patents. Also Tesla and and maybe one or two more Eastern European factories made tubes that were at least compatible. Videocolor had a long running series of curved tubes they called PIL-S4. I don't know for sure which Japanese brands used this construction.
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Old 16th Feb 2019, 3:26 pm   #78
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by InsertNameHere View Post
What causes the x-rays? Is it the EHT?

Understandable that 90 degrees were still being used, i’d imagine they were more universable with sets and parts? Easier to set up, too i’d guess?

Were 110 degree PILs more common? Perhaps as the technology advanced for both, it would’ve been better to combine to two to make a better CRT design l together?
Hi.

When the electrons are accelerated and strike the phosphors at the back of the faceplate, X-rays can be produced but the leaded glass will mostly absorb these. Increasing the final anode's potential (EHT voltage) above 25kV increases the risk of forward radiation from the front of the tube. I think it needs to be over 30kV for anything significant to happen.
Many early colour TVs that used the GY501/PD500 EHT valves had to employ screening around these to shield against X-rays. The PD500 shunt stabiliser valve being the main concern, though the EHT rectifier, GY501, could also produce X-rays is there was a heavy load on its cathode.

Setting up the PIL CRTs is about the same for any modern 90 or 110 degree CRT. This is a factory setting with a bonded yoke. Many 90 degree PIL CRTs have a multipole unit on the neck to set the purity and static convergence.

PIL S4 CRTs both 90 and 110 degree have a similar type of multipole unit. On the Philips 30AX and 45AX systems there's no external multipole unit, its preset internally during manufacture.
The really clever part of PIL CRTs is the yoke technology, in particular the way the line and field scan coils are wound to minimise raster distortion.

There weren't huge numbers of 110 degree deltas as the PIL CRT was coming on stream so I guess you could say 110 degree PILs were more common than 110 degree deltas.

Regards,
Symon

Last edited by Philips210; 16th Feb 2019 at 3:32 pm.
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Old 16th Feb 2019, 3:28 pm   #79
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Default Re: Types of CRT used in colour TV's.

Quote:
Originally Posted by slidertogrid View Post
In the late 1970's There was a 20" 20AX produced, used in the G11 with an offset final anode connection. I can't think of another set that used it.
Hi Rich.

The RRI T20 had the 20" 20AX tube.

Regards,
Symon.
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Old 16th Feb 2019, 8:01 pm   #80
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Default Re: Types of CRT used in colour TV's.

Also, Philips Germany manufactured a few 20" sets using the K12 chassis and a 20AX tube.
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