Toshiba RPTV red tint problem

Discussion in 'Archived Threads 2001-2004' started by GlennRC, Jan 14, 2003.

  1. GlennRC

    GlennRC Auditioning

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    I just bought a new Toshiba 50H82 RPTV and while I am generally satisfied with its performance thus far I am a bit disturbed with this noticable red tint on the screen (mostly away from the center of the picture). This is most noticable when changing channels, when the screen should be black or when watching DVD widescreen where it overrides the black bars. Is this normal? Can someone tell me what may be wrong?

    The glare is more of a problem than I had hoped and the picture is not as crisp as I hoped, even in HDTV.

    Also, if anyone knows Toshibas -- is it worth the $$ to upgrade to the 50HDX (what am I losing out on). Since I am still "trying out" the unit I need to know what I should do.
     
  2. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    Is this tinting on the left and right sides? If so ... sound like lens striping would help even out the colour consistency from edge to edge.

    Regards
     
  3. Jan Strnad

    Jan Strnad Screenwriter

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    I replaced the shiny protective screen with a piece of non-glare acrylic ($35 from a plastics store) and have been very happy with the result.

    You have to work slowly and very carefully, but it's just a matter of removing a lot of screws and not dropping a wrench on anything.

    You can also just remove the shiny protective screen and not replace it with anything, but I'm too nervous about damage to the lenticular screen to do that.

    Jan
     
  4. John Macri

    John Macri Stunt Coordinator

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    This doesn't sound right. I also have a new 50H82 and although it's still burning in (2 weeks old) the convergence is settling down somewhat, but I don't see the red tint problem. CSI Miami last Monday in HDTV was awesome. I didn't think the 50H82 could deliver that level of detail. Be sure to disable SVM and adjust your settings appropriately, this makes a big difference...
     
  5. Jan Strnad

    Jan Strnad Screenwriter

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    Michael,

    Can you explain color striping?

    I've read about it on the Keohi site but...I just didn't get it. The pictures meant nothing to me; they show a set with color striping, but since I don't know what it looked like before, I don't know what was added!

    If you can give a clearer explanation, I'd appreciate it!

    Jan
     
  6. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    greetings

    Typical layout of the three crts ...

    red ... green ... blue
    note that red points to the right side of the screen and blue points to the left side.

    Typically because of this alignment, right is too red and left is too blue. But if you torque the screws holding the lens for the red and blue crts a certain way, you can minimize the uneven light throw. This obviously takes too long to do in the factory assembly line as getting this right could take hours per set.

    What some makers do is introduce len striping to the crt's. When the maker does it, it is seen as these black metal strips they place in front of the crt and behind the lens. Too red on right side ... place black strip on red crt to reduce red light to right side. Do it enough and the tint goes away. Ditto for the blue and the left side.

    Sometimes they don't do enough of it or do it at all so the side tinting is still there to some degree.

    this is where the tweak comes in. Take some handy dandy electrical tape and mask off the side of the red crt which is throwing too much red light onto one of the sides. Reduce the amount of red light and the tint goes away. Remember that the image from the CRT surface is reversed and upsidedown.

    Tape never actually touches the lens surface. It sits on the plastic housing that holds the lens in place. Floating about 3 to 5 mm above the glass.

    oRedT oGreenT TBlueo

    This is the typical arrangement where the "o" is nothing and the T is the tape and on which side of the crt you are putting it.

    Obviously if the left side is red tinted then you have to tape the left side of the red crt.

    Regards
     

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