Sharp tvs and scan velocity modulation

Discussion in 'Displays' started by ThomasL, Feb 12, 2004.

  1. ThomasL

    ThomasL Supporting Actor

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    I have a friend who bought a Sharp 32 inch flat screen tv - 32F631 - and it suffers from horrible scan velocity modulation problems (as well as convergence issues). The problems are essentially rainbow shimmering effects on edges like people's noses and other sharp edges between two images on the screen. It also shows up on any vertical and horizontal lines. DVDs are almost unwatchable because of this effect. They are very disappointed with the set and before they return it, I wanted to check if anyone knew how to turn off scan velocity modulation on Sharp direct view sets. In addition to this problem, convergence seems poor which I've found to be the case on previous Sharps I've looked at with Avia. A good test of this is the star field in ST II right as the Reliant is being introduced early on in the film. On my Toshiba tv, the stars in the shot are white while on his set they twinkle in various colors.


    --tom
     
  2. Topher

    Topher Stunt Coordinator

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    Call Sharp, they have really good customer service. Explain what you want to do and I am sure they can help...
     
  3. ThomasL

    ThomasL Supporting Actor

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    Thanks.

    He's contacted Sharp but they have not gotten back to him.

    I happened to be in Best Buy today and decided to look at their other Sharp models/displays. This problem is systemic in their flat screen models. Adjusting the contrast or the sharpness does nothing to change the problem. My best guess is that it is an edge enhancement algorithm/SVM which is the root of the cause of the problem.

    Does anyone know if there is a way to turn off SVM from within the service menu on Sharp flat tube sets?


    --tom
     
  4. ThomasL

    ThomasL Supporting Actor

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    As a followup to this post, my friend was able to "solve" this inherent problem on the Sharp 32F631 (he tried two different sets - both had the problem) by purchasing the service manual and using the VSM Gain setting in the service menu. As always, I don't recommend anyone going into the service menu unless they have the manual and know what they're doing.

    Apparently, you'll need the service manual to map the more cryptic Sharp code in the menu to the more human readable 'VSM Gain'. It had settings from 0 to 3. He set it to 3 and it seemed to switch off the scan velocity modulation and all the rainbow affects he was seeing in edges of objects. The first set also had a tilt of 3/8ths of an inch but the 2nd one was better with only 1/8th so I told him that that is probably as best as he'll do since flat tube sets all seem to have some minor inherent geometry issues.

    He never used to think there was anything to tvs - "you just buy one, plug it in and watch it" - but now he's developed the "madness" as I call it [​IMG]

    cheers,


    --tom
     

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