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Toshiba 27WL46 DVI input resolution problem

Discussion in 'Televisions' started by kmm, May 4, 2005.

  1. kmm

    kmm
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    Just wondering if anyone has found a way of getting the Toshiba 27WL46 LCD TV to display the full resolution (1280x720) when feeding it with a DVI input from a PC ?

    Even with the PC running at 1280x720 and running perfectly OK on my PC's LCD monitor, if I then re-connect the DVI cable to my 27WL46 it only displays at 1024x768 (or could be 1024x720 seeing as the vertical resolution of the screen is 720 pixels). Anyway, it's not the full 1280x720.

    I had read that using the standard VGA connector works at full res, but I don't have a D-Sub cable, plus I'd rather use DVI for the quality.

    Any thoughts ?

    Thanks,
    Kevin.

    Addition to the above post...

    Managed to find a D-Sub cable and did some tests. Using the D-Sub cable I was able to get the full 1280x720 res in various refresh rates (and was offered all resolutions that my graphics card supports), whereas when I tried the DVI cable I was only offered a handful of resolutions (max 1024x768). Would I be correct in saying that the Toshiba "talks" to the PC via the DVI cable and limits the resolutions it will allow me to set based on some sort of internal hard-coded data on the Toshiba ?

    I take it that if this is the case, there is no (easy) way around it. I am either stuck with 1024x768 vis DVI or 1280x720 D-Sub ?

    Kevin.
     
  2. MikeK

    MikeK
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    Yes, depending on the video card and driver - but there is a little chip in the screen which holds EDID data, which tells the video card and driver what it's capabilities are.

    There's a little explanation here
    http://www.bluechiptechnology.co.uk...play_Identification_Data_(EDID) standards.pdf


    It may be possible to override the DDC/EDID settings in the driver, and use manual settings instead - how to do this will vary with the driver/video card combination in use. Powerstrip gives more options too, including the ability to create a monitor driver yourself!
     
  3. kmm

    kmm
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    Thanks for the reply Mike.

    After some digging and delving it is my intention to buy a HD device, either the Roku HD1500 or the Net Cinema HD, both of which interface directly with the LCD screen without the use of a PC, and hence unable to use Powerstrip.

    In this case, both devices output 720p signals, but I take it that if they were connected via the DVI cable the LCD screen would not display 1280x720 (as this appears not to be in the EDID data), but 1024x768 instead ?

    Kind of defeats the purpose of having a screen res of 1280x720 if the screen itself won't let you display it. Why would a company put such a limitation on a screen like this. What is the purpose ? Are all LCD screens limited like this ?

    Anyway, is there anything I can interface between the Roku or Net Cinema HD on the DVI cable that will basically tell the LCD screen to ignore its EDID data and display at full 720p res anyway ?

    Thanks,
    Kevin.
     
  4. MikeK

    MikeK
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    It's not the screen which needs to ignore the EDID data, but the device driving the screen.
    If that supports DDC/EDID, it will query the screen for EDID data, and then set resolutions appropriate to what it's been told by the info in the EDID.
    If it doesn't support DDC/EDID, no problem - it will never query the screen for that information - and even if the screen supplied it on it's own, it would simply be ignored.

    If the devices you mentioned don't support EDID, then you shouldn't have a problem there. However, before buying such a device, it may be a good idea to see if you can get 1280x720 going via the PC DVI first - just in case the issue isn't EDID related after all!

    I don't have either of those devices, (Roku or NetHD) so I can't help you on whether they support DDC/EDID or not!
     
  5. Joe Fernand

    Joe Fernand
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    kmm

    As MikeK suggests you may want to use your PC with Powerstrip to 'prove' you can actually run 1280x720@ 50 and or 60Hz into your Display; not always the case as 1280x720 is not a 'PC' format.

    If you can get it to run then a Gefen DVI Detective may allow you to get things working as required with your HD 'video' sources - we've used the DVI Detective a few times now to resolve a few EDID conflicts and it works pretty well.

    Its a plug and pray solution - you'll need to try the 1280x720 from the PC + DVI Detective to begin with and then try the HD Video Source with DVI Detective still in place.

    See http://www.gefen.com/kvm/product.jsp?prod_id=1378

    Best regards

    Joe
     

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