No Script, No Fear, All Opinion
RSS icon Home icon
  • EEVblog #554 – Sinclair FTV1 TV80 Flat Screen Pocket TV Teardown

    Posted on December 4th, 2013 EEVblog 17 comments


    Dave tears down a vintage 1984 Sinclair FTV1 / TV80 pocket TV and explains how the innovative 3 deflection system flat screen CRT works.
    Service Manual with schematics and theory of operation:

    http://eevblog.com/files/Sinclair_FTV1.zip

    Flickr Photos: http://www.flickr.com/photos/eevblog/sets/72157638306245666/
    Info page: http://www.thevalvepage.com/tv/sinclair/ftv1/ftv1.htm
    Guy who worked on the CRT: http://www.youtube.com/watch?v=VB7RgVqTgXI
    Forum: http://www.eevblog.com/forum/blog/eevblog-554-sinclair-ftv1-tv80-flat-screen-pocket-tv-teardown/

    Be Sociable, Share!
    • vimes

      Regarding that conductive repellant layer, Ben Krasnow did some interesting video’s about that:

    • Ross_ValuSoft

      Hi Dave.

      Because the viewer is facing the backside of the phosphor compared with the usual position of the viewer on the other side, I guess the Ferranti chip handled the scan reversal requirements. Does the service book/manual discuss that aspect?

      Cheers,

      Ross

    • Andy

      I noticed the wiki entry.
      Nice one.

      Further to the comment above, do you think the chip is converting the funny circular trapezium inherent in the tube, to a rectangle?

      Maybe it’s done with grid bias or magnets?

      Maybe not at all?

    • Danny Chouinard

      Hello Dave.

      CRT TVs and old Computer monitors very often generated the line scan signals from the HV power converter. Doing both in the same oscillator saves on parts.

      And by the way, that’s not a fresnel lens. Fresnels are segmented to save on thickness.

      http://en.wikipedia.org/wiki/Fresnel_lens

      Fascinating gadget, that TV.

      • Danny Chouinard

        Clicked submit too quick. I meant that lens looks smooth and not segmented. Bah! Maybe I’m wrong.

    • Dave C

      Whaaat? No power-on demo with VCR input or such?

      Would like to see it operate!

    • Worf

      The reason the image is stretched out is TV often used rectangular pixels, rather than square ones. So in this case, this probably puts out square pixels and uses the lens to reformat the screen so you’re not looking at obese actors.

      I.e., the pixels are taller than they are wide. Using it in this way means smaller deflection, as well as not having to design in the rectangular pixels – just do with square and use the pens to make it proper.

      • N2IXK

        A monochrome CRT TV image doesn’t HAVE any “pixels”.

        It has a fixed number of horizontal scan lines, but the brightness is completely analog. The phosphor is a continuous layer, not broken into dots/stripes/bars as is needed in a color CRT to accomodate the 3 different color phosphors.

        The horizontal resolution of the image is *theoretically* infinite. In reality it is limited by particle size of the phosphor, phosphor chemistry, electron beam size/shape, gun design, etc.

    • huh

      This CRT is just gorgeous. If I couldn’t find the spare chip to make the TV work again I would seriously consider removing the tube then building the circuitry to drive it to show waveforms of ambient noise (not that hard), then stick the whole thing into a perspex case with the entire CRT visible, which should be spectacular when the heater is lit.
      As a geek living room ornament it would be excellent.

      • Kirill

        The view must be spectacular but the lifespan of the tube is pretty limited. It is OK to enjoy it from time to time but keeping it lit all day and night will almost definitely kill the cathode heater within less then 2 years and I woldn’t guarantee more then 4 months.

    • Phil zl3pah

      Hi,
      I worked at Sinclair shortly after the time the TV was developed. However I was based in Winchester, not Cambridge where the TV was developed.
      I was in Cambridge for a meeting and saw the original working glassware for the tube. Sinclair at times was very short of cash and when the dev team asked for GBP 5,000 for the first glassware Clive said they did not need it and he would get them the glass in 5 minutes. He came back with a milk bottle and said put it in that. They did and it apparently worked – the screen phosphor was deposited on the inside of the bottle, the gun assembly was inserted in the bottle neck, the whole thing was evacuated and the glass neck sealed and it worked. It formed part of a display (sic) on the tube development which hung on the wall in one of the meeting rooms in Sinclair HQ in Cambridge.

    • ac

      Hi Dave, could you order a Sony DPS-T1 and do a thorough review and teardown? It uses a new panel type not previously sold and is large enough that viewing technical books and datasheets could be finally practical.

    • ac

      Correction. I meant DPT-S1. Who comes up with these names ;)

    • http://www.sparkybruce.com Bruce Benson

      Hi Dave,

      I loved this teardown so this afternoon when I visited the TV’s designer (Jim Westwood who is now at Amino Communications near Cambridge) I had to mention it to him.

      When I left him this afternoon he was watching it and smiling. If you have any questions about it (or other Sinclair goodies) I can put you directly in touch with him.

      Some of his stories about the good old Sinclair days are amazing.

      He is now busy working his magic on set top boxes.

      Thanks

      Bruce

      • http://www.eevblog.com EEVblog

        Nice to know Jim watched it and liked it, thanks!