Brightness Adjusting Itself on a Panasonic Set

Discussion in 'Displays' started by Bryan Ri, May 5, 2004.

  1. Bryan Ri

    Bryan Ri Screenwriter

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    I own a 20" flatscreen Panasonic for my bedroom, and I have an issue on it where the brightness will adjust itself, creating a flicker on the picture.

    Does anyone know why this is happening, or if they've heard of anything like this before?

    SHould I boot this one for a similar model?

    Please help [​IMG]


    Bryan
     
  2. Allan Jayne

    Allan Jayne Cinematographer

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    Are you playing DVD's through a VCR? Usually (not for all disks) this result in flicker because the Macrovision anti-copy codes on most disks jam most VCR's even if the VCR is not recording. You need to connect the DVD player directly to the TV or if absolutely needed with an RF modulator (aoubt USD $30. from Radio Shack) in between. This is not the problem if the brightness changes while watching TV shows too.

    If you are unable to leave both the VCR and DVD player plugged into the TV input jacks ([probably video and S-video respectively) and have them both work, boot the TV anyway. Do not buy a similar (or different) model with just one video input, just one S-video input, and just one selection on the remote for video in or AV in, because you can only connect just one thing to it at a time.

    Does the TV have a sensor that brightens and dims the picture as room light changes? If you are watching in the dark, the TV itself could be activating its own sensor. Put some tape over the sensor if the TV has it. This is probably not the problem if you are viewing witht he lights on.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  3. Bryan Ri

    Bryan Ri Screenwriter

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    Thanks for the response Allan.

    The VCR is only hooked up in conjunction with my cable input; the DVD player is hooked up through the TV on a separate input.

    I'll have to check on the brightness sensor, but as far as I know, there is none. The screen will flicker based on the colors that are on the screen.



    Bryan
     
  4. Jack Briggs

    Jack Briggs Executive Producer

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    Bryan, sounds like that little Panasonic has poor DC restoration -- which results from a skimpy power supply (quite common in sets of that screen size). This means your deeper blacks will "float" depending on the brightness of the rest of the image, whereas a set with a beefier power supply will maintain consistently deep blacks no matter how bright other parts of the picture are.

    About the only thing you can do is make sure your white level (i.e., "contrast") is set reasonably low. The dark areas of the picture will still float, only less noticeably.
     
  5. Bryan Ri

    Bryan Ri Screenwriter

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    Thank you for your help Mr. Briggs.

    I think I'm just going to buy a 27". I think I saw a fairly nice one for under $200, so what the hell.

    Thanks again everyone.



    Bryan
     
  6. JustinG

    JustinG Stunt Coordinator

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    You know, I was in Fry's yesterday looking at the larger LCDs, ie the 42" to 50" rptvs. I noticed the brightness flicker on the Sony 42". It was quite annoying. It seemed to do it pretty often also, at least once per minute. Maybe it is an inherent problem with the LCD tech.
     

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