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Mullard 25" rectangular colour CRT available in 1965.

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Till Eulenspiegel
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Found this by chance in the pages of the June 1965 Wireless World.  Mullard Limited were supplying for appraisal and set development a 25" colour CRT to manufactures in 1965.  Possibly this new tube was given a development number rather than the familiar type A63-11X.  TV sets fitted with the then new rectangular colour tube were on sale in the United States in 1965.

Scroll down to page 281.  Well worthwhile reading the other articles in this particular issue.

http://www.americanradiohistory.com/Archive-Wireless-World/60s/Wireless-World-1965-06.pdf

Till Eulenspiegel.

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Topic starter Posted : 29/11/2016 10:23 pm
Nuvistor
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Thanks, just downloaded the copy, sit back and enjoy the read.

Frank

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Posted : 29/11/2016 10:27 pm
Till Eulenspiegel
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The mid sixties was the decade when things were starting to happen, transistors were beginning to appear in home electronics and the recent introduction of the reinforced faceplate CRTs improved the appearance of TV sets. The shape of CRTs seems to determined by the developer of the first tube so the A63-11X will be essentially the same as the RCA equivalent.

You have to go back to the early 1950s when the first rectangular 14" , 17" and 21" mono CRTs appeared in America. The UK and European CRT manufactures had no other choice but to follow the lead set by the tube developers the other side of the Atlantic.  It's possible that the shape of the first 21" FST mono CRT was  determined by Toshiba.

Till Eulenspiegel.

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Topic starter Posted : 30/11/2016 12:03 am
Nuvistor
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I wonder if there was a patent license deal done with respect to the technology used in the rectangular style screen, rimband safety features etc between the CRT manufacturers.

This could account for the follow the leader approach to those technologies. I don't think they could have patented the rectangular screen shape but the manufacturing process could be. The Rimband/Panarama safety feature I thought could be patented and the designs are so similar i wonder who came up with it first.

The Thorn colour CRT factory in Skelmerdale were made with technology from RCA, RCA did have a stake in the Thorn subsidiary though. 

All supposition on my part.

Frank

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Posted : 30/11/2016 11:16 am
Till Eulenspiegel
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Hi Frank,

           I did once believe many years ago that the development of a particular valve or CRT was result of some sort of technical committee.  The industry would issue a demand for a special valve or tube for a specific purpose and a group of wise people would be tasked to design such a device. Of course we now that is not so and the development of such things is done by an individual manufacturer, for example the Philips "World Series" valves such as the PY81, PY80/1 ECL80, EF80 etc.  Mazda developed their own unique valves which not replicated by any other manufacturer, 30PL1 30FL1, 20P4 etc.  In 1953/4 RCA made the first mass market colour CRT, the complex and difficult to make 15GP22 and only a year later CBS came up with their version of the shadowmask tube. Then shortly after RCA produced the first 21" round faceplate shadowmask CRT, the 21AXP22A.  The round 21" CRT was the norm until the mid sixties.

An interesting colour CRT is the 22" "square corner" A56-120X, a tube that I'm certain that was developed by Philips. It was introduced early 1968 and first fitted in certain dual standard colour sets such as the G6. In fact if you think about it in 1969 Ferguson had to make do with that rather unsquare 22" CRT type A55-14X, developed by RCA I guess. The squared up 22" colour CRT didn't appear in a BRC set until 1971. 

I'm sure we can trawl up more information about this subject.

 

Till Eulenspiegel.

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Topic starter Posted : 30/11/2016 5:10 pm
Nuvistor
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From memory the first CRT's used in the U.K. I was told that the shadow mask was more suited for 525 line sets and moire patterns were more pronounced. The A56-120X shadow mask was designed for 625 line sets, giving better pictures and less moire patterns.

How true that information is I cannot say, could be salesman talk or it could have come from the technical support people, too long ago.

I shall have trawl, it will keep me out of the pub, is that a good thing? cheers

Frank

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Posted : 30/11/2016 5:21 pm
Till Eulenspiegel
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nuvistor said:

I shall have trawl, it will keep me out of the pub, is that a good thing? cheers

Frank  

 Hi Frank, It's OK to go to the pub but remember to keep within BMA guidelines and make sure not to drink more than 13 units per week, what ever those are.   Nanny state rules OK.

A new monochrome CRT development appeared in late 1967, this was the square corner 20" CRT. This new CRT was first installed in the RGD RV217 and KB KV217 TV sets, the first tube of this type of tube to be marketed in UK.  The A51-10W CRT was made by the ITT associate company SEL in Germany.  Philips introduced the A51-120W in March 1968 and the tube was first installed in the model 20TG230, a follow on model from 19TG210.   

Worth noting that the first slim 110 degree CRTs were introduced in the USA in 1957, Mullard announced a similar CRT in late 1958.  Pye was the first UK manufacture to install a 110 degree CRT into a TV set, the PV110 was announced late 1958.  CRT was made by Pye Group company Cathodean.

Till Eulenspiegel.

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Topic starter Posted : 30/11/2016 9:40 pm
Nuvistor
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The 20 inch square CRT's I thought looked very smart, I do remember Cathodean, used their CRT's at one time, put one in my Ekco T433 for our first home  in 1970. They also made crystals as well.

We only started with ITT in the 70's so I did not see that SEL tube, but yes the A51-120W, saw many Mullard ones.

I have not found any more about the A56-120X and the claim about designed for 625. 

Just had an hour watercolour painting, one of my other hobbies, will carry on searching later.

Frank

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Posted : 30/11/2016 10:03 pm
Nuvistor
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The information I was given about the A56-120X is correct, good leaflet on the web site. There is comment about it being a unique feature to Mullard for British CRT's, a dig at Mazda/RCA perhaps?

http://www.philipstv.org.uk/blog/early-philips-colour-tv/components/cathode-ray-tubes/

Frank

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Posted : 30/11/2016 11:13 pm
Till Eulenspiegel
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Hi Frank,

                We'd like to think that the developer of the A56-120X was Mullard but according to the Radiomuseum it would seem that it was Telefunken in Germany that could have been the original developer. However, I do recall seeing announcement of the dual standard 22" Philips G6 in a March 1968 trade magazine.

Perhaps Mullard or Philips licenced the design of this popular CRT to TFK, or was it the other way around? 

From the Radiomuseum:  www.radiomuseum.org/dsp_multipage_pdf.cfm?pdf=d_tfk_bildroehrenwerk_ulm_donautal.pdf

Technical info:  www.radiomuseum.org/tubes/tube_a56-120x.html 

Till Eulenspiegel.

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Topic starter Posted : 01/12/2016 11:18 am
Nuvistor
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I dont suppose we will find out who was the first, its also possible that the shape and style are the same but with internal differences and again no easy way to know.

 I read the article in the first link, lots of info,  the second tech info link returns a 404 error for me.

Frank

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Posted : 01/12/2016 3:12 pm
Till Eulenspiegel
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Hi Frank,

            A56-120X:     Visit the Radiomuseum.org and just search Tubes + Tr.

Till Eulenspiegel.

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Topic starter Posted : 01/12/2016 10:36 pm
Nuvistor
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I had a look at the page, now you will know, I  have forgotten but there were two tubes, an A56-120X and an A65-120X,  I don't remember a Mullard version of the A65 only an A66-120X.  If this is correct, perhaps they were two different designs of the A56-120X and A66-120X from Mullard and Telefunken. Completely conjecture though.

Did Thorn produce an A65-120X?

Surprising how much I have forgotten with being out of it since 1980.

Frank

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Posted : 02/12/2016 1:01 pm
Till Eulenspiegel
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Hi Frank.

               I kinda remember the Thorn CRT was the A67-120X and there was also the A67-200X. These tubes were of RCA origin.   In the late seventies Thorn-EMI produced a 26" set that employed an A67 type of CRT which was claimed to have special phosphors, the TV sets were designated as 3745 and 6645, a horrible thing which employed the 9800 series chassis.  The CRT was short lived.  Considering the 8000 series started as a nice honest economy 17" model then progressed to the 19" 8500, then even later to the decent 8800 22" set and finally finished up with the awful 9800 series.

Actually some Mullard branded A67-120X tubes were installed in certain Philips G8 sets.  Mullard didn't make this type of tube so must have bought such tubes from Thorn or even RCA.

Till Eulenspiegel.

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Topic starter Posted : 02/12/2016 9:41 pm
Nuvistor
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I saw very few Thorn colour CRT's with not dealing with Thorn TV's. The Thorn/RCA factory was not far from Wigan and was not open for very long, about 5 years.

if you want a read about the closure this is about the best and accurate obtainable. It's from Hansard.

http://hansard.millbanksystems.com/commons/1976/jan/22/thorn-colour-television-factory

Frank

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Posted : 02/12/2016 9:51 pm
crustytv
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Till Eulenspiegel said
Considering the 8000 series started as a nice honest economy 17" model then progressed to the 19" 8500, then even later to the decent 8800 22" set and finally finished up with the awful 9800 series.

Till Eulenspiegel.  

fright

Time and age must be mellowing you David, back in 2008 over on UKVRRR you felt the 8800 was "best forgotten". Perhaps in another eight years you may mellow further and start liking the 9800.winkgrin_gif

Must admit I'm a bit of a fan boy when it comes to Thorn I've collected most and have 2000, 3000 MKI, 3000 MKII, 3500, 8500, 8800, 9000, 9905 and finally 9600, still need to find a nice 8000 to plug the gap. I'm also living in hope that one day I get the hens teeth Thorn 4000 but I think I might never happen. Some reckon I should get TX9 and TX10 but they're too "modern" for me.

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Posted : 02/12/2016 10:04 pm
Jayceebee
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Till Eulenspiegel said
Hi Frank.

                In the late seventies Thorn-EMI produced a 26" set that employed an A67 type of CRT which was claimed to have special phosphors, the TV sets were designated as 3745 and 6645, a horrible thing which employed the 9800 series chassis.  The CRT was short lived

Till Eulenspiegel.  

That would be the "Black Matrix" CRT which was available in 22" also. I believe it was a black coating between the phosphor dots which absorbed light falling on the screen and improved the contrast ratio. I must be the only one who liked the 9800, even with a bog standard A56-120X fitted as a replacement it produced a much better picture than an 8800, with a single mod of a resistor on the PSU were also very stable. The inertia kick start operation was a bit unusual but not that difficult to work out what was going on.

One of the most unusual kick starts was the Philips GR1-AX which pulsed the volume control pin of the jungle IC from the HT rail to start the line oscillator. Work that one out without the circuit description.

My other guilty pleasure was the Rank A816 mono chassis mob_gif.

John.

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Posted : 02/12/2016 11:37 pm
Nuvistor
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From that Hansard report it states that there were no UK made small screen CRT's, never thought of it at the time but all the 20inch and under U.K models I saw used Japenese CRT's. RBM 823 chassis and the truly awful Pye CT 200, think I have that number correct. What's more I don't know if the Japanese CRT's supplied in the U.K. sets were inferior but the sets did not give as good a picture as the Hitachi or Toshiba sets of the same era. 

We sold a lot of TV's through the 70's and the small screen sets (18-20inch)were very popular.

I don't know why but towards the end of the 70's the Hitachi and Toshiba sets reliability seemed to decline.

Frank

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Posted : 03/12/2016 12:11 am
Till Eulenspiegel
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Hi Frank, in the late seventies Mullard Limited did receive a grant from the Callaghan government to set up production of 20" in-line gun CR tubes, the tube we know as the A51-570X and later the A51-580X. Questions were asked in Parliament  about the fact that Mullard was essentially a foreign firm as being a part of Philips but as Thorn had given up making CRTs there was no other alternative to help out Mullard.   The A51-570X was first fitted into the later versions of the 9000 series.  While on the subject of CRTs didn't Mullard make some late production A56-120X CRTs with quick heat cathodes?

Hi Chris, I certainly wouldn't go out of my way to look out for a 8800 series TV with the exception maybe the HMV 2725 and that would only be because of the attractive all wood cabinet.  The rest of these sets have nothing more than Fablon covered chipboard cabinets and that's not nice.   As for looking out for a 4000 series set, now that would be certainly be a truly interesting addition to your collection, but the likelihood of one ever turning up is remote.  The model I used to work on was the posh HMV 2726 console model.   I still have few spare parts for the 4000 series.

Hi JayCeeBee,   rest assured I knew how the 9800 series power supplies worked. I had had no other choice because I had to look after the things but I thought that Thorn designers had taken the 8000 chassis concept too far.  Much better was the magnificently over engineered 9600 series. 

Till Eulenspiegel.

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Topic starter Posted : 03/12/2016 11:52 am
Nuvistor
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Quick heat A56-120X , possible but i don't  remember them, A120-140X/A120-410X (normal/quick heat) I do remember but they were 110 degree.

Hitachi produced some quick heat 22inch CRT's with the heaters fed from the LOPTX. I think but could be wrong that these were directly heated, chokes feeding each heater. I had problems with the CRT's and also easily missed dry joints on those chokes that gave the impression of a low emmision gun on the CRT. I think they were 90 degree, that's needs confirmation.

I remember mods to replace a quick heat with a standard type, that could have been the Mullard -410X or that Hitachi CRT.

There is no doubt in my mind the the reliability of Hitachi and Toshiba was not as good in the late 70's very early 80's than 7 or 8 years earlier.

Frank

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Posted : 03/12/2016 1:29 pm
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