To All Mac Doctors: Help me diagnose this problem...

Discussion in 'Mac Basics and Help' started by redAPPLE, May 24, 2007.

  1. redAPPLE macrumors 68030

    redAPPLE

    Joined:
    May 7, 2002
    Location:
    2 Much Infinite Loops
    #1
    hi guys.

    i have an iBook G4 800 mhz. it boots up until i get a gray screen. no apple logo, no nothing.

    i can connect the iBook in terminal mode. and it works fine.

    is it possible, that this is a backlight problem?

    i would love to have your help. thank you.
     
  2. epochblue macrumors 68000

    epochblue

    Joined:
    Aug 12, 2005
    Location:
    Nashville, TN
    #2
    If you can log into it remotely, it would seem to be booting up just fine, and the problem is in the screen somewhere.

    This may sound like a silly suggestion, but you might try putting a really bright light directly behind the Apple logo on the case, you might be able to get enough light into the case to see whether or not the screen is on. That would at least help diagnose the problem.
     
  3. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #3
    If the screen is grey, it's not a backlight problem.

    What do you mean when you say you can connect in terminal mode? Do you mean you're using telnet or ssh or rlogin to log into it while it's on with the blank grey screen?

    I would try resetting all the system settings in open firmware:

    Cmd-Opt-O-F at boot
    type these commands following each line with <enter>

    reset-nvram
    set-defaults
    reset-all

    After the last one, it should reboot. Note that they have hyphens and no spaces.

    Now see if it boots into the OS. If it doesn't, next try inserting an install CD/DVD and holding down the "c" key during boot to boot off the disc.

    (The rest of this is less likely to help...)

    If that doesn't work, try holding down the cmd-s during boot to boot into single user mode. You should boot up to a text interface. Type:

    /sbin/fsck -fy

    And press <enter>. Let it do its thing.

    Try that much and report back. ;)
     
  4. redAPPLE thread starter macrumors 68030

    redAPPLE

    Joined:
    May 7, 2002
    Location:
    2 Much Infinite Loops
    #4
    connectin in terminal mode should mean, when i boot up pressing the "T" key...
     
  5. redAPPLE thread starter macrumors 68030

    redAPPLE

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    #5
    kernel panic :eek: is what i get after doing the above (tried 3 times. 3 kernel panics).
     
  6. redAPPLE thread starter macrumors 68030

    redAPPLE

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    #6
    i get a "blue" screen. i don't see nothing.
     
  7. NuDarwin macrumors member

    NuDarwin

    Joined:
    Mar 26, 2007
    #7
    1) its impossible for you to get a kernel panic in open firmware (there isn't a kernel loaded yet)
    2) hlding down the "T" key is target disk mode. this makes sense; target disk mode relies on info on the mac's logic board, while booting into os x relies on data in the hard drive.

    to resolve your "doesn't boot up all the way problem" i would suggest running DiskWarrior to repair the directory. if you don't have access to a copy of diskwarrior, use the os x install disk that came with the ibook to run disk first aid on your drive.
     
  8. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #8
    When does the crash occur? Do you get as far as the screen that has the open firmware introduction and the text prompt? If this isn't working for you, then I would address this first before I bothered with DiskWarrior, etc. I think the latter is a great suggestion, but it's like NuDarwin said -- order of operations. The firmware comes before the disk drive and the kernel. And at this point your computer is not running properly even at that level.

    If you are not able to get the open firmware procedure to work, try the (less extensive) procedure of holding cmd-opt-p-r during reboot. If it works correctly, you should get a chime and then a second chime after a delay, if I remember correctly. But in any event, it'll be different, so you'll know.
     
  9. NuDarwin macrumors member

    NuDarwin

    Joined:
    Mar 26, 2007
    #9
    just remember: continue to hold down Cmd + Opt + P + R until you hear chime #2. Don't let it go. Otherwise, extremely good advice.
     
  10. redAPPLE thread starter macrumors 68030

    redAPPLE

    Joined:
    May 7, 2002
    Location:
    2 Much Infinite Loops
    #10
    i'd try the tips when i get the chance. thanks for the help guys. i will keep you posted.
     

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