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Forum 141

That's not a Colour Telly... It's a lab instrument!

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Forum 142
(@Anonymous)
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My current restoration project is the Tektronix 650HR Video Monitor.

These were intended for video quality control of the station's signal, or for use in Master Control as the reference monitor.  It can be rack mounted. Weighs about 23kg.

Made by Tektronix during the 1980s they were expensive and typically only found in network control rooms and engineering operations.

This one has the NTSC decoder, under-scan, pulse cross, and aperture controls in addition to the usual Brightness, Contrast, Chroma, and Hue. There's A, B, and A-B input selection, and internal or external sync, Typically the convergence and set up controls (on the left side) are behind a locked panel. Has regulated internal supplies, AC mains transformer, and stabilized 19kV EHT.

Here's a couple of off-screen PIX.

DSCN5222_resize.JPGDSCN5216_resize.JPGDSCN5220_resize.JPGDSCN5221_resize.JPG

This unit was shipped to me from Quebec City, Canada. (A road journey of 5,100km and arrived safely) It required little electronic repair; just a replacement of the large electrolytic in the 5V linear regulator. The power switch handle is broken off, I have obtained a factory spare.

To Be Continued!

 
Posted : 14/11/2016 4:45 am
Nuvistor
(@nuvistor)
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The CRT would cost more than many complete TV's when that was made. Just shows what's possible with the system.

I was reading a short note in one of the UK technical mags from the 60's, not sure which mag now. The few who had been to the US and seen CTV were not impressed  by the quality of the pictures seen by the general public, hotels rooms, bars some homes but commented on the excellent quality seen when they visited the studios. I presume the studio were using the full bandwidth video before being converted to NTSC for transmission but I could be wrong.

No doubt there were many sets with poor aerials and poorly setup with the normal viewers. Under good conditions there should be little difference beteen NTSC and PAL pictures all things being equal, good transmission and a decent properly setup receiving installation.

Frank

Frank

 
Posted : 14/11/2016 8:40 am
Terrykc
(@terrykc)
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nuvistor said
... The few who had been to the US and seen CTV were not impressed  by the quality of the pictures seen by the general public ...

During the 405/625-line debate in the early 60s a bigwig from one of the US networks was over here and said that we should definitely go for 625-lines but added that the quality of our 405-line pictures was better than those of the US networks!

I was setting up a Baird colour set in a customer's house when the funeral of Bobby Kennedy was being shown on BBC2.

Apart from the general poor quality of the pictures, for a long time a shot of the motorcade travelling along a straight road away from the camera was shown, with the camera sufficiently high up to see along the entire line of cars.

Unfortunately, the camera convergence was so bad that there was a column of red tail lights, one on the left hand side of each vehicle, and an identical column travelling up the field that bordered the road!

When all else fails, read the instructions

 
Posted : 14/11/2016 11:08 am
Cathovisor
(@cathovisor)
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When I worked on the 1996 Atlanta Olympics, all the signals were distributed in NTSC within the broadcast centre and we made all our programmes in NTSC, only turning them to PAL at the last moment. It was the last Olympics made in analogue video.

Apart from lacking a little bandwidth, the pictures were very good indeed and the higher frame rate was a bonus.

 
Posted : 14/11/2016 12:06 pm
Nuvistor
(@nuvistor)
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The pictures of the Mexico Olympics in 1968 were excellent pictures.

Frank

 
Posted : 14/11/2016 12:39 pm
Cathovisor
(@cathovisor)
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Even more remarkable when you consider that the converter for Mexico involved six 3.33ms quartz delay lines as part of the 50/60 conversion...

http://www.vtoldboys.com/arc10.htm#

 
Posted : 14/11/2016 6:24 pm
Focus Diode
(@focus)
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I have the BBC Handbook 1969 which mentions the electronic 525 NTSC to 625 PAL standards converter.

Apparently the original prototype resulted in reduced height the brilliant team at the BBC were able to rectify in time for the 1968 Mexico Olympics.

 
Posted : 20/11/2016 9:07 am
Nuvistor
(@nuvistor)
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The pictures from Mexico were so good I did not understand why some other American TV shows were so poor in picture quality. I think one was "Rowan and Martins Laugh in". Picture size was reduced, I was told this was due to conversion, that I can accept although the Mexico pictures I remember were full size( could be wrong, long time ago).

The colour on the "Rowan" shows had bands of different hue about 2 inches wide across the screen, the frequency responce was also poor, smeary pictures.

Now whether that was due to conversion or a poor videotape, presume it was tape, I don't know. The banding across the screen I was told was due to poor setup of the quad video heads, whether on record or playback, again I don't know.

Not much I do know is there bash_gif

Frank

Frank

 
Posted : 20/11/2016 9:21 am
Terrykc
(@terrykc)
Posts: 4005
Member Rest in Peace
 

Focusdiode said
Apparently the original prototype resulted in reduced height the brilliant team at the BBC were able to rectify in time for the 1968 Mexico Olympics.  

Yes it did. The reason was that it did the 60/50 field conversion OK but didn't generate 625 lines from the 525 line input, so the height was reduced.

To compensate, the line length was reduced to maintain the correct aspect ratio which, of course, meant there was a black border all round.

Once the 525/625 bit was sorted out, we got full sized pictures.

When all else fails, read the instructions

 
Posted : 20/11/2016 6:38 pm
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