Can't get DVI -> HDMI out of my gt120 (2009 octo)

Discussion in 'Mac Pro' started by gjarold, Aug 2, 2011.

  1. gjarold macrumors regular

    Nov 14, 2007
    I have a 2009 octo with 2 gt120 cards, giving me four total outputs.

    3 of those outputs are connected to Dell u3011s with no problems.

    The 4th output (DVI) I have attached to a tiny DVI-HDMI adaptor plug, and then attached a high quality HDMI cable from there to my large NEC display.

    When I turn on the NEC display, my three monitors wink in and out to indicate a new display has attached, and further, in display properties, I see a rectangle appear in the "arrangement" tab of my display properties.

    So everything seems fine ... but there is no picture on the NEC display.

    Further, the NEC display seems to be very confused - the on-screen controls get VERY slow and laggy, takes almost 30 seconds to move from menu item to menu item ... but if I unplug the HDMI cable from the display, it goes back to normal and is not "confused" anymore.

    Why am I not getting plain old HDMI output out of my DVI port, and what could my gt120 be feeding my display that would cause it to be so "confused" ?

  2. gjarold thread starter macrumors regular

    Nov 14, 2007
    One more note - the little DVI->HDMI adaptor I am using is DVI-D (single link) ... but that should be fine, since the display is only 1920x1080 ...

    and the mac pro is detecting it properly - when I go into system profiler, it sees the NEC display, shows the proper model number, resolution, etc.

    The mac pro thinks all is well - there is just no picture on the display.
  3. blunti macrumors 6502a

    Mar 15, 2011
    perhaps the NEC display's panel might gone wrong? did you try the same cable/adaptor in one of the dells you have?
  4. gjarold thread starter macrumors regular

    Nov 14, 2007
    No, the panel is good. I connected it to the mac pro with displayport and it works fine.

    For a variety of reasons I need to get it running over DVI ... any ideas why it's not ?

    On paper, this should work, right ?

    gt120 -> DVI -> HDMI cable -> display

    As I said, the mac pro thinks it is working fine...
  5. gjarold thread starter macrumors regular

    Nov 14, 2007
    Anyone ? Am I not correct that this config is supposedly bulletproof, since "HDMI *is* DVI" ?
  6. drac macrumors newbie

    Oct 27, 2004
    Try a different cable.

    I would try a cheap dvi-hdmi cable just to make sure the dongle/cable isn't causing the issues.

    Bulletproof is a difficult description since many AV components have had compatibility issues with other components from different manufacturers. (Many originally due to HDCD handshake issues.)
  7. gjarold thread starter macrumors regular

    Nov 14, 2007
    Hmmm... ok, yes, I should rule out the cabling.

    With that in mind, can anyone tell me a DVI<->HDMI cable that is KNOWN to properly work between a gt120 and a plain old 1920x1080 HDTV ?

    As in, I will buy whatever amazon item you tell me to - I just need someone to tell me "I know this cable works with between gt120 DVI and HDTV HDMI"

  8. Cindori macrumors 68040


    Jan 17, 2008
    if the display is a TV, try messing around with it's display settings in the TV menus.

    also, you say single dvi is fine for 1900x1080, but if the display supports higher res it will not show anything with single dvi, even if you try to use lower res.

    also... i'd just unplug everything except the display you are having problem with, and see if it works then
  9. YanniDepp macrumors 6502


    Dec 10, 2008
    It can also depend on other things, such as the length and quality of the HDMI cable.

    Example: I have a 2009 Mac mini. I can't get a picture through a Mini DP -> HDMI dongle and a 5m HDMI cable. I can get a picture through the Mini DP -> HDMI dongle and a 2m HDMI cable. I can get a picture with the same TV, the 5m HDMI cable and an XBox 360.

    As a workaround, I now use a 5m VGA cable to connect my mac to my TV. It's lower quality, but it seems more reliable with distances > 2m.
  10. gjarold thread starter macrumors regular

    Nov 14, 2007
    Well, again, I think the first thing to do is just get a cable that is _known_ to work ... so regardless of price, etc., if you know of a DVI<->HDMI cable that works between gt120 and plain old HDTV, tell me the item number and I will just buy that and go from there...

  11. jenzjen macrumors 68000

    Aug 20, 2010

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