iMac dvi second monitor black flash

Discussion in 'iMac' started by sportster, Sep 21, 2010.

  1. sportster macrumors 6502

    Joined:
    Jul 7, 2010
    Location:
    Katy, TX
    #1
    I have a mid 2007 20" iMac. 2.4GHz Intel Core 2 Duo and ATI Radeon HD 2600 PRO with 256MB of GDDR3 memory. Current OS is 10.6.4

    I've been trying lately to get a second monitor to work properly. I'm using a 20" Dell SP2009W.

    The second monitor (dell) randomly flashes black\off. As if it loses power or signal. It seems to be completely random. I tried the same monitor/cable/mini-dvi adapter with my MacBook. It works 100%, on all resolutions. Also running bootcamp with XP, XP and the second monitor work 100%. Never had any issues, only on the mac side.

    I do not believe there is any issues with the monitor or cable. I though it could be my video card or dvi port. But, it seems to work fine while booted in Windows. I've tried all the updates I could find, it is very annoying not usable at all.

    Any tips or suggestions?
     
  2. sportster thread starter macrumors 6502

    Joined:
    Jul 7, 2010
    Location:
    Katy, TX
    #2
    Bump...


    I reloaded the OS. I did not do a full clean install, only stuck the disk in and let it do its thing. It did seem to help, but I still am getting the black flashing. Just not as much.

    Does anyone have any ideas or experience with this?
     
  3. sportster thread starter macrumors 6502

    Joined:
    Jul 7, 2010
    Location:
    Katy, TX
    #3
    Is it just me or what? It's sad that the second monitor works with zero issues when booted in Windows. I always figured the Windows side to give me issues not the OS X side.


    Bump again... any help or suggestions? I'm guessing a full clean install would be the next step?
     
  4. sportster thread starter macrumors 6502

    Joined:
    Jul 7, 2010
    Location:
    Katy, TX
    #4
    Seriously? Is anyone out there? This flashing on the second monitor is driving me nuts!!

    It's almost to the point where I would rather run my iMac in Windows all the time. Because, there is no issues with the second monitor there.

    Is there anything else that can be done? I've eliminated the monitor, cable, adapter, or hardware in the iMac as being the issue. It has to be a software issue with OS X (10.6.x).

    Would it make any difference if I did a clean wipe of the hard drive then a full fresh install of the OS? But, would using my Time Machine backups just re-install the issue?
     
  5. sportster thread starter macrumors 6502

    Joined:
    Jul 7, 2010
    Location:
    Katy, TX
    #5
    After a few months of not using my second monitor at all, I've deiced to try to get this worked out. I've been working with Photoshop a lot, and could use some extra desktop space to work on.

    All the issues are still the same. The second display, ran from my iMac with the apple dvi adapter to the 20" dell monitor, flashes off randomly. If I bootcamp into XP on my iMac the second monitor runs all with no issues at all. :(

    I've tried the monitor, cable, and dvi adapter with a laptop with no issues.

    I still think it's a software issue with OS X. Since it works with no issues while booted in XP, I would think that would eliminate a hardware issue. In September I did a clean install of Snow Leopard, and then manually restored my documents via my Time Machine back up. I didn't want to use the time machine restore fearing that there was a sys file bad and it would just re install the issue.

    I am really desperate for suggestions or tips! My iMac is way out or warranty so I don't think Apple would be much help for me.
     
  6. sportster thread starter macrumors 6502

    Joined:
    Jul 7, 2010
    Location:
    Katy, TX
    #6
    I went to the Apple store yesterday to buy a mini dvi to vga adapter to try out on my imac. I also talked with them about the issues I have been having.

    First off they said bring it in and they will diagnose it for free. They also suggested reseting the pram. Which I did when I got home. That had no affect on the issue.

    I then tried the vga adapter with the same monitor. Problem gone. I'm not really sure what that proves. Seeing how the dvi adapter and cable worked great in my MacBook. Oh well I guess. Second monitor is now working 100% via the vga adapter.
     
  7. product26 macrumors 6502a

    product26

    Joined:
    May 30, 2005
    #7
    We had one of the first core 2 duo imacs that didn't play well with certain DVI cables. The adapter was a brand new from apple, & the cable came brand new with the monitor. Swapped the DVI cable and fixed everything. Funny thing is, the DVI cable works just fine on other machines & monitors.

     

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