2009 iMac: white screen after boot chime, no response to keyboard input

Discussion in 'iMac' started by segers909, Jun 29, 2015.

  1. segers909 macrumors regular

    Joined:
    Jun 7, 2009
    Location:
    Belgium
    #1
    I've got a 2009 Core 2 Duo iMac that's refusing to boot. It just keeps displaying a white screen forever. Holding down the Alt key does not display boot options and holding down the PRAM-reset keys elicits no response. I've tried installing a different hard drive (I figured maybe it was short circuiting or something) and pulling one bar of ram and then the other. None of that makes any difference. I'm getting desperate and would appreciate any suggestions. Even just some way to confirm a dead logic board would be helpful, as I could then go ahead and order a replacement.
     
  2. Dadioh macrumors 65816

    Dadioh

    Joined:
    Feb 3, 2010
    Location:
    Canada Eh?
    #2
    Pure white screen may mean that the backlight is on but no video signal arriving to the display. Possibly a bad video card. But before doing anything else you should do an SMC reset and PRAM reset.

    https://support.apple.com/en-ca/HT201295

    Another check to see if it is the video card would be to hook up and external monitor via the display port connector. You will probably need a DP->VGA or DP->DVI adapter if you don't have a DP monitor
     
  3. segers909 thread starter macrumors regular

    Joined:
    Jun 7, 2009
    Location:
    Belgium
    #3
    I've had some breakthroughs: I left the iMac on its white screen for about an hour while holding down the Alt button with a weight. The boot menu showed up. Selecting Macintosh HD just froze it again (I left it for several hours to see if it would unfreeze but it didn't). I then put weights on the PRAM reset buttons and left it at its white screen, and sure enough, the iMac rebooted with a louder chime after an hour or so. It didn't seem to fix anything though.

    I then suspected the hard drive might be to blame after all. I installed a different hard drive onto which I had put a bootable Yosemite installer and nothing else. An hour after booting the Mac, it loaded up the installer. Everything inside the installer works but is extremely slow. Click something, wait a minute, the Mac reacts.

    So I wanted to run a hardware test. I used this Apple Hardware Test download and this trick (using Terminal inside the OS X installer to bless the hardware test on a usb drive). After rebooting and waiting an hour the hardware test loaded up, again extremely slow. Language selection took 5 minutes, and probing the hardware took so long I went to sleep. I've now had a weight on the "T" key to start the hardware test for about an hour and it has yet to start. This really is very, very weird. Anybody ever experienced something similar? Guesses as to the cause?
     

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