Boot issue w/ iMac24, display issues

Discussion in 'iMac' started by TTVert, Feb 10, 2014.

  1. TTVert macrumors newbie

    Joined:
    Feb 10, 2014
    #1
    This is my first post so thanks for any help you can provide me. I've not touched an apple product since the IIe so it's been quite some time for me. Anyway, I have an Imac24 (A1225) that recently has ceased to boot. It would just get the grey screen w/ the apple logo and the rotating dial would eventually freeze. I'll list what troubleshooting steps I've done to save some time below. I've been researching before running out of options and asking for some help and have read there is a hardware test that can be performed from recovery or (app cd 2). However I have the install disk (OS 10.6) and one application cd, nothing stating application cd 2 so perhaps I am missing this?

    Steps I've taken
    1. Booted to recovery partition, OS, safe boot, from installation CD but hangs before it gets there
    2. performed a verbose boot and It hangs in one of two spots.
    3. Put a different HDD in and tried a clean install from install cd but it also hangs.
    4. Booted from each RAM chip separately to attempt to isolate a bad RAM chip.
    5. Reset PRAM/VRAM and SMC
    6. It WILL boot to single user mode but I'm clueless as to what to do from the command line of a MAC


    Note: when it does hang on the install cd the video gets a bit messed up at the top 1/8th of the screen or so if that makes any difference. Also noticed once the screen turned green while booting from installation cd which makes me suspect the video card. Just not sure that the video card would cause the lack of boot issue or not.

    Verbose boot stop points:
    Sandbox: authd(69) deny file-write-create /private/var/db/mds/system/mdsDirectory.db.sh-9f6a2a6f-g4UcrT
    or
    SMC::smcReadKeyAction ERROR: smcReadData8 failed for key BEMB (kSMCKeyNotFound)

    Thanks again and I hope I've done some diagnostics steps to help you guys point me in the correct direction..

    Dave
     
  2. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #2
    Excellent diagnostic steps. I concur that it is likely a bad video card or a failing logicboard.
     
  3. TTVert thread starter macrumors newbie

    Joined:
    Feb 10, 2014
    #3
    Thanks, aside from just putting in a known good video card, is there a way to determine if it is the system board or the video card that is at fault? Can you tell me where I can find this hardware test that is mentioned? I believe the OS on this iMac is 10.6 so the d at boot will not work correct? I've now read the hardware test is on the application disk 2 or the install cd. As stated I see an application cd (doesn't mention a cd number and isn't bootable) and the install cd which of course hangs so if the HW test is on there I'm screened anyway. I just want to get this working to learn my way around mac's a bit more.

    BTW, I've already disassembled this thing and played about with it, reseating everything and checking the thermal grease on the video card in hopes it was an overheating issue but no luck. I'm a die hard pc guy but the engineering and design behind apple products is by and far the best I've seen in a computer product. Kudos to apple on R&D.

    Dave
     
  4. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #4
    The only publicly available hardware test will only test the ram. An Apple Store or certified Mac repair shop will be the full hardware test that can check everything. That model is considered "Vintage" by Apple. Thus, they won't repair it (unless you bought it and live in California) and they may not diagnose it at all.
     
  5. Brian33 macrumors 6502a

    Joined:
    Apr 30, 2008
    Location:
    USA (Virginia)
    #5
    Hi! I've got the same model (A1225) 24" Early 2008 iMac, purchased in May 2008. There is an Apple Hardware Test that came with mine, so I would think yours would have one too.

    My machine came with Leopard (OS X 10.5.2) on 2 discs. Are you sure the OS X 10.6 disc you've got isn't a purchased upgrade disc you got later? The AHT is only on the discs that actually came with the iMac (because it's specific to the hardware, I believe).

    My discs are uniform gray with a white border around the perimeter and white lettering, labelled "Mac OS X Install Disc 1" and "Mac OS X Install Disc 2". Disc 1 has the notation (in rather small letters): "To use Apple Hardware Test, hold down the D key as the computer starts up." I believe (but I'm not sure) this means to hold D while booting from the disc itself.

    I have run the AHT on my machine a long while ago, but I don't remember much of what it claims to do, or whether it would tell you what you need to know.
     

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