iMac G5 iSight failing...

Discussion in 'PowerPC Macs' started by aross99, Aug 4, 2009.

  1. aross99 macrumors 68000

    aross99

    Joined:
    Dec 17, 2006
    Location:
    East Lansing, MI
    #1
    I have an iMac G5 iSight 17, that is having strange issues.

    When you restart it comes up to the white screen with the apple, but USUALLY there is no spinner. When this happens, it hangs and the fans kick on.

    Occasionally, I can get the spinner to come on, and it will boot. When it boots, it seems pretty normal, except that it doesn't provide enough power for external Firewire drives. It also seems to get hung up from time to time - like the hard drive is not working.

    I have zapped the PRAM and reset the SMU - no effect.

    I am most successful in getting it to boot, by holding down option and then selecting the drive and booting. I have made sure the drive is selected in the startup control panel -no difference. DOn't know why this would make a difference.

    I can boot from the Leopard DVD, and the hard drive checks out OK. occasionally, the drive won't show up though - especially if the is an external USB peripheral like a USB powered drive.

    These machines are a SOB to get into, so I haven't pulled the drive yet. I was able to clone it to an external drive and reinstall Leopard - no difference.

    I would think it had a bad hard drive, except for the fact, that I can clone the entire drive (65GB), and reinstall Leopard on it w/o any errors. I also can't boot off an external drive, because the drive doesn't seem to get enough power - most of the time. Seems like a lot of drive access for a bad drive.

    I am leaning towards a power supply issue ($100 replacement part). Maybe the power supply isn't providing enough power to spin up the drive at boot time? Maybe that explains the weirdness with the external firewire drives?

    Since the machine is useless if I can't get any farther, I am going to try to crack it open tonight and verify that the hard drive is OK, in an external enclosure.

    Assuming that works, I think I may have to order a new power supply.

    Any other suggestions?

    Anybody seen anything like this?
     
  2. geoffreak macrumors 68020

    geoffreak

    Joined:
    Feb 8, 2008
    #2
    Sounds like your logic board is on the way out.
     
  3. aross99 thread starter macrumors 68000

    aross99

    Joined:
    Dec 17, 2006
    Location:
    East Lansing, MI
    #3
    Wouldn't a logic board issue be more of a complete failure?

    It seems likes it is getting too much functionality for that.

    Then again, I guess I have never seen an iMac logic board failure...
     
  4. geoffreak macrumors 68020

    geoffreak

    Joined:
    Feb 8, 2008
    #4
    Well, the power supply would only be of issue if the machine was completely shutting off randomly or during heavy workloads.

    The logic board is made up of many smaller elements. When one breaks, the entire board must be replaced even though most of the board may still work.
     
  5. MTI macrumors 65816

    Joined:
    Feb 17, 2009
    Location:
    Scottsdale, AZ
    #5
    If/when you open the iMac up, examine the logic board capacitors for bulging or leaks. It's simply amazing how a $0.15 part can bring an otherwise fine personal computer to its knees.
     

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