Previous 1 2 Next 18 Replies Latest reply: Aug 4, 2010 2:35 PM by BDAqua
Carl Ketterling Level 1 (15 points)

I apologize that this is a complex post, but I want to give you all the steps I've already tried. I'm not yet ready to throw this machine away.



Power Mac G4 (QuickSilver 2002), 2 x 1GHz



Computer was running Mac OS X without issues. One day, the computer would not fully boot. It starts to boot with the Apple graphic and spinning pinwheel, but after some time, displays the circle with a line through it.


*Tests Performed*:

• Attempted to boot to TechTool CD ... same problem.
• Attempted to boot to Network Boot Disk (Mac OS X) ... same problem.
• Attempted to boot to FireWire Disk (Mac OS X) ... same problem.
• Replaced all memory with known-good memory ... same problem.
• Disconnected all IDE/ATA cables and attempted to boot to network disk ... same.
• Found a similar machine's Apple Hardware Test CD. Booted to that and ran all tests ... PASSED WITHOUT ERROR.
• Booted from Mac OS 9 Installer WITHOUT PROBLEM
• Installed Mac OS 9 to hard drive WITHOUT PROBLEM
• Still booted from CD, opened System Preferences and selected Startup Disk ... computer froze and mouse would not move.
• Used option key to select boot drive. Selected OS 9 ... machine froze at "Welcome to Mac OS"
• Zapped PRAM ... same problems.
• Reset PMU ... same problems.
• Tested internal battery. It shows 2.7 volts (lower than spec), so replaced it with fresh battery (measuring 3.4 volts). Computer WILL NOT POWER ON!
• Removed battery ... computer returns to previous problem state.
• Installed original battery ... computer returns to previous problem state.


I'm eager to hear what other people think about these symptoms. Please provide ideas on how to troubleshoot/fix this problem.

iMac 27", Mac OS X (10.6.4)
  • BDAqua Level 10 (122,276 points)
    Hi Carl, not complex at all! In fact, I don't think I've ever seen as complete, precise posting of what's the problem is or what's been done ever, congrats!

    One thing you didn't list & may or may not help...

    Does it boot into Open Firmware with CMDOption+of ?

    reset-nvram (press Enter)
    set-defaults (press Enter)
    reset-all (press Enter)

    Does it Safe Boot from the HD, (holding Shift key down at bootup)?
  • Carl Ketterling Level 1 (15 points)
    Well, it didn't boot, but the symptoms changed. Now, I get the Apple graphic and the pinwheel, and then I get the following text across the top of the screen:

    System Failure: cpu=1; code=00000008 (Unaligned stack)

    A quick search on this site makes me believe that one of the CPUs is going bad (or something related). Maybe the OS 9 CD doesn't use as much cache or doesn't use the 2nd CPU, and that's why it would boot. Is that what you think?

  • BDAqua Level 10 (122,276 points)
    Good find, yes, OS9 normally only uses one CPU, unless special APPs use it specifically.

    One possible test is...


    * Power Fractal for Mac OS 8-9

    Down on this page...

    It'll tell you or give you a choice of how many CPUs to use or are available, as well as Altivec.
  • Texas Mac Man Level 8 (46,565 points)
    Suggest you repeat the Apple Hardware Test. Running the AHT in Loop Mode is an excellent troubleshooting step for finding intermittent hardware problems. It is especially useful when troubleshooting intermittent kernel panics. If Loop Mode is supported by the version of the Apple Hardware Test you are using, you run the Extended Test in Loop Mode by pressing Control-L before starting the test. Looping On should appear in the right window. Then click the Extended Test button.The test will run continuously until a problem is found. If a problem is found, the test will cease to loop, indicating the problem it found. If the test fails, be sure to write down the exact message associated with the failure.In some cases, RAM problems did not show up until nearly 40 loops, so give it a good run.

     Cheers, Tom

  • Carl Ketterling Level 1 (15 points)
    Thanks, guys. I'm going to try Tom's suggestion of running in loop mode. I'll leave it until tomorrow morning and see how it's working. Will let you know.

  • Carl Ketterling Level 1 (15 points)
    Well, I did try Tom's advice. The hardware test disk has been running for about 24 hours now (I stopped it on loop #121). Then reboot to the hard drive with Mac OS X installed, and the failure returns.

    A bit more information, though. While it boots to a Mac OS 9 Installer CD and is able to install Mac OS 9, it can't boot to the Mac OS 9 hard drive that it installed.

    Having a computer that almost works is much more frustrating than one that just stops working!!

  • BDAqua Level 10 (122,276 points)
    Carl, is the partition that OS9 is installed on larger than 200GB?
  • Carl Ketterling Level 1 (15 points)

    Mac OS 9 is installed on a 75GB drive.
    Mac OS X is installed on a separate 500GB drive.

  • BDAqua Level 10 (122,276 points)
    Is the OS9 disk a Master Drive, or Slave?
  • Carl Ketterling Level 1 (15 points)
    First, my apologies for the delay in getting back to this problem.

    I wasn't sure where you were headed with this question, but I opened the system to look at the drives. OS 9 was the slave disk. I took out the OS X drive and jumpered the the OS 9 drive as master/single.

    Now, I can boot OS 9 and get through the setup assistant.

    What do you think was causing OS 9 not to boot before?

    Does this lead to a solution for OS X, or am I stuck with an OS 9 ONLY machine?

  • Carl Ketterling Level 1 (15 points)
    I guess I spoke too soon.

    I shut down the system and was going to wait for your reply, but I reread the thread and thought I should try using Power Fractal. When I tried to reboot the Mac, it gets to the "Welcome to Mac OS" screen and hangs.

    Unless you have any other suggestions, I'll assume it's a heat-related problem with the processor cards (based on previous reading) and consider the unit trash.

  • Jeff Level 6 (11,477 points)
    "Unless you have any other suggestions, I'll assume it's a heat-related problem with the processor cards (based on previous reading) and consider the unit trash."

    If you narrow it down to a processor issue, replacing the processor with a comparable used one or a faster third-party one is always an option. Many Forum regulars have upgraded their processor cards just for the speed/performance boost, and not because the original failed. You could check eBay for a used one or Other World Computing for third-party processor, like this one. If you think it's better to retire the computer than invest any $$ in it, it does have some value for the remaining working parts in it.
  • BDAqua Level 10 (122,276 points)
    Does it boot if it cools for a few hours?

    How about if you disconnect the drive then reconnect it?
  • Carl Ketterling Level 1 (15 points)

    Thank you for the suggestions. I'll look on eBay for a cheap processor to try.
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