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Rear Projection TV

Discussion in 'Troubleshooting and Repair' started by Patty, Dec 4, 2010.

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  1. Patty

    Patty

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    Dec 4, 2010
    Toshiba model 57H84-Vertical lines in picture, any solutions?
     
  2. shrtrnd

    shrtrnd

    3,743
    482
    Jan 15, 2010
    Check the obvious first.
    What are you using for your input signal?
    Are the lines on all the channels?
    Even if you have cable, there might be a problem with the signal to the TV.
    Before you do anything to the TV itself, check that that input cable, wherever it's coming
    from is not causing the problem. The second important thing to check, is if you have
    some new or relocated electronic device near (or close) to the input cable.
    You may have a circuit problem, but move the cable around some, to see if you inducing
    a stray signal onto the input. An actual antenna will be even more prone to this type
    of a problem.
     
  3. Patty

    Patty

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    0
    Dec 4, 2010
    Rear projection tv problem

    I have checked all the cables and the Direct TV receiver, they are working correctly, I attached another tv to the receiver and it worked properly.
     
  4. Resqueline

    Resqueline

    2,848
    2
    Jul 31, 2009
    Vertical lines are rare, and then usually caused by (more or less synchronous) interference. Can you describe the lines better, or get a shot of them?
     
  5. Patty

    Patty

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    Dec 4, 2010
    The lines are light blue about 1/2" wide and seperated about 1/2". They are sometimes very light and sometimes a little bolder, sometimes clean lines and sometimes herrinbone. If I leave the tv on they stay the same, but if I turn the tv off overnight, the next morning the screen is a mess of lines and colors for ten to fifteen minutes, then back to the above.
     
  6. shrtrnd

    shrtrnd

    3,743
    482
    Jan 15, 2010
    This probably won't help, but you're describing problems similar to a failed degaussing coil on an old style CRT picture tube. I don't remember much about working on the old projection TV's. If you're sure there's nothing new which could be screwing-up your input signal, you may have a circuit problem in the TV itself, which partially compensates for itself when the set electronics warms up. Hopefully somebody who's more familiar with projection TV's will get on this site, and offer better help.
     
  7. Resqueline

    Resqueline

    2,848
    2
    Jul 31, 2009
    Yep, someone experienced with that, or at least a wiring diagram would be helpful.
    To me it sounds like a digital signal somehow has found its way into the video signal. Can you count how many lines there are in total across the picture? Is it NTSC?
     
  8. Patty

    Patty

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    Dec 4, 2010
    There about 36 lines across the picture. I have tried the picture with a DVD movie off a player, and the lines are still there. If it were interference, wouldn't it dissapear with a different input? What is NTSC ?
     
  9. alfa88

    alfa88

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    Dec 1, 2010
    Blanking circuit faulty?
     
  10. alfa88

    alfa88

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    Dec 1, 2010
    Cover 1 color projector at a time to see if it is specific to 1 tube.
     
  11. Resqueline

    Resqueline

    2,848
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    Jul 31, 2009
    NTSC = Never The Same Color = American TV system, as opposed to PAL = Perfect ALways = European TV system. They have different deflection frequencies.
    I was hoping to be able to calculate/ recognize the offending frequency and thereby perhaps the offending circuit (inside the TV). Check out alfa's last idea, it's good.
     
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,396
    2,777
    Jan 21, 2010
    I thought it was

    NTSC = Never Twice the Same Colour
    SECAM = Something Essentially Contrary to the American Method. (French)
    PAL = Peace At Last
     
  13. haflalali

    haflalali

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    0
    Dec 13, 2010
    first i have to say sory for my inglish, i have don same problem C R T projector tv there are
    three crt tiube red green & blue, i replaced some small codensers from vertical side after
    i gote good clear pictuer, but i do no your tv crt or 3LCD,
     
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