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Multiple monitors using radeon x600 and windows wp

Discussion in 'ATI' started by marc, Feb 19, 2007.

  1. marc

    marc Guest

    Hello everybody,

    I was wondering whether someone could help me figuring out why I can't
    get the second monitor of my system working. The system is a modern
    pc, dell 3GHz, with a radeon x600 videocard, running windows XP sp2.
    Two monitors are connected to the videocard (one videocard), using one
    cable which splits into two connectors. The system recognizes that
    there are two monitors, but the second monitor remains blank. I have
    switched the connectors and both monitors are working. I have run the
    windows troubleshooter and addressed all points but to no avail.
    Display drivers are installed and the connection type is pci. Any help
    is much appreciated.

    Best regards,

    marc, Feb 19, 2007
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  2. marc

    Geoff Guest

    where are you looking to see there is 2 monitor connected ?
    device manager ?

    go in display properties, settings like this:
    click advanced
    and go to displays

    ahh crap, i bet you have the new crappy CCC drivers :(
    well thats where you setup dual monitor in older CP drivers.....
    Geoff, Feb 20, 2007
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  3. marc

    Paul Guest

    That cable sounds suspicious.

    First, there is some background info here:

    Here is a sample picture of an X600:

    The bottom connector is VGA (analog) and there is definitely
    only one monitor interface on that connector.

    The top connector looks to be DVI-I.

    DVI-I consists of two interfaces, a digital interface and
    an analog interface. If you connect a "VGA dongle" to a
    DVI-I connector, it is possible to extract just the analog
    portion of the interface, giving the standard 15 pin VGA.
    Functions on there, include the RGB signals that give you the
    display, plus the SCLK/SDATA that the computer and monitor use,
    so the computer can read the EDID from the monitor and understand
    what resolutions it supports.

    If you plug a DVI-D cable into the DVI-I connector, then
    you gain access to just the digital version of the output.

    On a DVI-I cable, normally you use the analog output or
    you use the DVI-D output, but you don't use both at the
    same time. At least, without deciding what to do about
    SCLK/SDATA. I don't think two monitors can share the same
    serial interface, but I could be wrong. (I cannot think
    of a reason they'd want to support multiple devices on
    the bus, but maybe they do.)

    So, I'd try connecting one monitor to each of the
    connectors shown in the atech.com catalog picture.
    Using separate cables.

    The video card has two logical blocks inside, for
    driving the two monitors, and the faceplate
    can have up to three connectors on it. Usually you
    are limited to using specific combinations (2 of 3)
    of the connectors. And on a DVI-I, you generally only
    want to try to use one set of the output signals at
    a time, as SCLK/SDATA may be shared, and I don't know
    what would happen if you tried to use both. If SCLK/SDATA
    only went to one monitor, and not the other, then you
    could be in the dangerous situation of sending a higher than
    acceptable resolution to one of the two monitors. (Like if
    one monitor, the one with SCLK/SDATA, was a 1280x1024 LCD,
    and mthe second monitor was an old 1024x768 analog CRT.)

    Alternate names for the SCLK and SDATA, are SCL and SDA,
    or in this picture, DDC Clock and DDC Data. The key in this
    picture calls the DDC Clock and DDC Data, part of "Plug and
    Play", as it allows the computer to figure out what the
    monitor characteristics are, and I think it only expects
    to find *one* monitor.


    OK, I found an example of your cable here.


    I would use only one of those two interfaces at a time.
    Actually, I wouldn't use that adapter at all, because it leaves
    the signals an open stub, when one connector is not used.
    If you need to extract the VGA analog signals, I'd prefer
    to use one of the following, because it doesn't do anything
    with the digital signals at all. This is a DVI-I to
    VGA dongle, which typically comes packaged with certain
    brands of video cards. The cheaper the card, the less
    likely you are to find one of these included in the package.
    I won't buy a video card, unless this is listed as being
    in the box (because I hate having to buy one later).


    By means of the VGA dongle, you can connect a VGA monitor
    to the DVI-I connector. Or if you use a DVI cable, you can
    connect a DVI monitor. I'm not really that crazy about that
    Y shaped cable, due to the sharing of SCLK/SDATA, and
    leaving the unused signals flopping around on the connector
    that is not being used. (Maybe the video card is clever
    enough to turn off the unused signals, but I don't know
    that for a fact. At least with the analog interface, it is
    possible for the video card to sense and detect that
    something is connected to the analog RGB signal. Since not
    all display devices have DDC on them, probing the serial
    bus and looking for EDID info, is not a sufficient test
    that a display device is connected.)

    Paul, Feb 20, 2007
  4. marc

    marc Guest

    Hi all,

    If you had this problem, what did solve it was that in the display
    properties there were two images of the monitors and one was grayed
    out. After right-clicking you could enable it.

    regards Marc
    marc, Mar 19, 2007
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