Need help diagnosing video noise.

Discussion in 'Home Theater Projects' started by RobP, Jan 17, 2005.

  1. RobP

    RobP Stunt Coordinator

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    When I run a straight s-video signal from my reciever (for switching and on screen display) to my tv the signal has a lot of artifact, grain, noise (I'm not sure how to describe it) that runs horizontally all over the television. First I thought the reciever might be introducing the noise so I ran a composite cable from reciever to the tv and it was fine.

    I then kept the composite hooked up to the tv but used an s-video/composite adapter plug, to plug the other end into the receiver's s-video out, the picture was fine. So then I thought it might be the tv so I did the same thing in reverse.

    I ran a composite cable out of the reciver and used the adapter to plug it into the s-video input of the tv. It was fine again. Maybe it was the s-video cable itself i thought so I tried running three different S-video cables directly and all had the same noise in the video.

    So it seems for whatever reason the noise only presents itself when I run an s-video cable from receiver to tv. Any ideas on what it could be?
     
  2. Kevin. W

    Kevin. W Screenwriter

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    Are you using a cable or sat box? If so have you tried running straight from the box to the tv and see what the PQ is like.

    Kevin
     
  3. Allan Jayne

    Allan Jayne Cinematographer

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    >>> I then kept the composite hooked up ...

    Hint for testing and also for all other purposes:

    Do not have both the S-video and yellow jacks plugged on the same input bank (Video 1, Video 2, etc) of your Television. Unpredictable results can occur. It is not unusual for the composite to not work if the S-video jack is occupied.

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

    Also worth trying:

    How does S-video from DVD player directly to TV work out? (Even if you are using component video, try the S-video just for a few minutes now.)

    Switch back and forth between Video 1, Video 2, etc. on the Receiver, there could be noisy switching connections.

    Try unplugging everything, VCR, games, speakers, etc. from your receiver and then reconnect just the items that were giving you trouble. Start with no cables between anything and anything except one S-video cable from receiver output to TV, and nothing but menus can be seen. If it works OK now, then connect one thing at a time back and see if and when the problem comes back.

    On many cable and satellite systems, even digital, a few channels will come through better with composite video especially if your TV has a 3D comb filter.
     
  4. RobP

    RobP Stunt Coordinator

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    Thanks for the link. I'll try what you suggest but it will take a few days. Ill let you know if I figure it out.
     

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