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Use the chassis of a TV set (without picture tube) as a video souce

Discussion in 'Electronic Repair' started by John, Feb 25, 2007.

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  1. John

    John Guest

    I have a 5 years old RCA tv that required a new picture tube just
    after de warranty had expired and the price for the installation of a
    new tube was ridiculous. It was a good lemon but it was a lemon.
    I would like to use the set as one more video source to drive an
    external monitor ( it has pic on pic).
    If I power the set without the picture tube and yoke load, will it
    give nothing but sparks?
    Then what do you suggest that I should disconnect in order to use it
    as I mentioned.
    I have the service manual some where and if I get some encouragement
    from you, I will look for it.
    Thanks in advance.
    John
     
  2. ian field

    ian field Guest

    The line scan coils are part of the tuned resonant circuit so if you remove
    them it will overload the PSU. Removing the CRT leaves you with a free
    hanging EHT lead at 25kV and you can't remove the EHT transformer because
    certain windings supply feedback for the sync separator.
     
  3. Jamie

    Jamie Guest

    I really don't think that is a good idea.
    The HV in the system is an integral part of not only supplying HV,
    but, supplying other signals required for various processes like Low
    voltage sources, signal references to monitor sync etc..
     
  4. James Sweet

    James Sweet Guest


    What on earth would you get out of doing this? Just junk it.
     
  5. You can get all of the free VCRs you want. Use them.


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  6. Arfa Daily

    Arfa Daily Guest

    Not to mention several other LT rails, which may or may not be used in the
    signal stages, and probably a pulse that's used by the colour decoder. On
    some FBT's, the EHT lead is removable. If that set is one of them, you may
    be able to remove it and fill the plastic tube that's left behind, with
    silicone rubber to stop the lightning flying out of it, but as Ian says, the
    scan yoke is an integral part of the circuit, and would have to be left
    connected.

    Arfa
     
  7. John

    John Guest

    Thanks to all of you.
    I am going to use the old VCR idea.
    John
     
  8. PeterD

    PeterD Guest

    Especially when an old mechanically dead VCR will do exactly what the
    OP wants! <bg>
     
  9. Arfa Daily

    Arfa Daily Guest

    However, I thought that the whole point of asking the question, was so that
    you would be able to make use of the TV set's features, such as PiP. You
    won't find too many VCR's laying around that can do that ...

    Arfa
     
  10. ian field

    ian field Guest

    Don't they have DVB-T set top boxes where the OP is?

    In the UK a basic freeview decoder price has plunged to about £25, I
    recently bought a freeview DVR with 160Gb hard drive (80 hours recording)
    with dual tuner and PIP for £99. Well worth the money to watch one programme
    while recording something on another channel.
     
  11. John

    John Guest

    Correct. I have one , JVC S8000 U that has that, may be I can
    use it. It's an old but excelente machine that can also use S tapes .
    I don't know if those tapes are available today


    John
     
  12. Paul Feaker

    Paul Feaker Guest

    Why would you need to take out the picture tube to use it like described?

    Couldn't you just do what you plan on doing with the picture tube intact?
     
  13. Sofie

    Sofie Guest

    Why bother with the size and inconvenience..... use a mechanically
    challenged scrap VCR for the purpose.
    It is smaller, uses less power and is in a nice contained cabinet.
    Daniel Sofie
    Electronics Supply & Repair
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  14. Hey sofa, instead of a VCR, why not use a DVD player so you can watch
    this DVD I have.

    they show a fat boy screaming and crying while he's being beaten with
    a baton.
     

  15. I like the old, separate TV tuners for the early portable VCRs. I've
    converted two or three already. Basically, you remove the large cable
    with that plugs in in place of the camera. Find the audio and video,
    and mount a couple connectors on a plate to cover the hole where the
    old cable was removed. Takes me 10-15 minutes to convert one. I left
    one at a TV station as a spare off air demod. The video engineer like
    it better than the $20,000 Tektronics system because it was a closer
    match to what a typical home TV saw when it was fed to his monitors. He
    used the Tektronics for quality measurements, but my converted equipment
    for live shows.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
  16. No, he's already watching the DVD of you butt ass naked with a bucket
    of KFC.
     
  17. Sofie

    Sofie Guest

    Michael:
    Yes.... the 2pc VCR units were a good candidate to permanently separate.....
    I did many like you did, and in addition, separated the VCR, added 12 V
    power and A/V connectors so that it could be used without the turner and AC
    power supply..... many customers used them for their RVs and trailers.
    Most of these 2pc units, however, were old enough that their TV tuners were
    not fully "cable ready" with all of the current cable channels so in today's
    world, I use a cheap, discarded VCR that still powers up.... makes a decent
    tuner with today's capabilities... but as you know, most of those older
    tuners were more sensitive and usually worked better for fringe off-air
    reception.
    Daniel Sofie
    Electronics Supply & Repair
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  18. That's why I used them, and we weren't worried about cable channels
    so they were the perfect choice. Set it up, stick it into the bottom of
    a relay rack, and feed it to the A/V switcher/router.

    If someone wants the cable channels, they have little choice but to
    use the newer VCR tuners.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
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