ATI HD 2600 XT hdmi signal loss to LCD TV after input switch or power off

Discussion in 'Mac Pro' started by UberD, Mar 3, 2008.

  1. UberD macrumors newbie

    Mar 1, 2008
    Here is something aggravating... Hook up a $3K machine to a $1.5K display and have to hard power down your $3K machine to get the picture back.

    When I boot everything is fine. If I change input to TV or power off the display, when I power back up or switch back to hdmi input screen displays error, can't read signal check output device. I have read on this forum about a issue similar with ATV but not with MacPro. In my google searches I read some issues with Vista, but no resolution... thought to be a ATI driver problem. Does anyone know of a tweak to fix the ATI 2600 XT to remember the tv signal after you change inputs or power off the display?

    I have tried:
    update Sharp LC-42D64U firmware
    searched Google for hours
    posted on Apple forum (someone sent me a link to a Gefen DVI detector)
    Posted on ATI's site, but the 2600 is not even in their support listing for Mac yet
    Played with settings on tv
    Tried unplugging and plugging back in cable
    Tried leaving display off for hours and powering back on (with and without cable connected)

    Any suggestions would be appreciated.

    System is new MacPro 2008, 8 core 2.8, ATI Radeon HD 2600 XT, MacRaid card with 4 WD 750gb in Raid 5, 1 apple stock 320gb for OS/programs, 1 lg GGC H20L optical drive, 2gb of mac ram. All software updates installed 10.5.2 and graphic update included.

    Display is Sharp LC-42D64U with latest firmware U0709111 installed
  2. almostinsane macrumors regular

    Feb 9, 2008
    When you turn off the display the ATI card in turn turns off the DVI port. When you turn the display back on the card is having a problem receiving the EDID info from the display that says the supported resolutions. This happens to PC ATI and nVidia cards. The only solution is the DVI detective as it will give your ATI card a constant signal and the EDID info will remain intact.
  3. xraydoc macrumors 604


    Oct 9, 2005
    Sounds like an HDMI issue with your TV. I have an LG monitor connected to my Mac Pro via HDMI and don't have an issue, but then again its a computer monitor and not a TV. There are plenty of HDMI issues between AV equipment, let alone PCs/Macs.
  4. UberD thread starter macrumors newbie

    Mar 1, 2008
    ATI HD 2600 XT hdmi signal loss to LCD TV after input switch or power off

    Thank you both for your reply. I ended up getting dvi detective. It works great. For anyone else having a similar problem. After I ordered the dvi detective from Gefen, I came across a potentially cheaper solution. But, since Gefen shipped same day, I could not cancel my order to try it. There are DVI to RGB connectors which would enable you to run full 1080 and not have to worry about EDID and any other hdcp junk. The cable I found was something like $14 bucks verses the $130 for the dvi detective plus. Yeah, I had to get the plus.... I am kinda' a sucker for things like that.

    Thanks again.
  5. thydzik macrumors newbie

    May 18, 2008
  6. phreich macrumors newbie

    Jan 25, 2009
    Thanks, thydzik your solution worked for me!

    Many thanks to thydzik for his simple and elegant solution to this problem with ATI cards losing their connection to hdtv's.

    I have posted an explanation of his solution and the link to his solution on a number of other forums in the hope that the word gets out.

    I just wish that ATI had fixed this issue in their drivers. Their newer drivers may resolve this for some of their display adapters but not for my ati radeon x700 pro using the latest driver as of 1/22/2009. Many others in other forums are also reporting that the issue continues.

    Again, many thanks for thydzik providing an easy workaround.

    Note that thydzik's solution seems to written to work in Windows -- so I am not sure why it is being posted on a mac forum.

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