iMac G3 Not Powering On.

Discussion in 'PowerPC Macs' started by Goftrey, Jun 3, 2013.

  1. macrumors 68000

    Goftrey

    Joined:
    May 20, 2011
    Location:
    Wales, UK
    #1
    I have used my Rev.A Bondi-Blue iMac for a good while now solely as a jukebox. It's been doing the same task flawlessly for months, day in, day out - until today.

    When the power cable is connected to the iMac, the computer (haven't located where abouts the noise is coming from) makes a very high pitched, tinnitus-like noise. Then, when I push the power button in - the noise becomes louder.

    I tried to record both a video & audio sample but the mic. just won't pick up the sound.

    There's no startup chime, fans, display. Nothing.

    Any ideas?
     
  2. macrumors 603

    justperry

    #2
    Sounds like a bad capacitor, probably in the power supply.
     
  3. macrumors 65816

    Lil Chillbil

    Joined:
    Jan 30, 2012
    Location:
    California
    #3
    backing up justperry it does sound like a capacitor
     
  4. thread starter macrumors 68000

    Goftrey

    Joined:
    May 20, 2011
    Location:
    Wales, UK
    #4
    I finally got around to opening the iMac up & diagnosing the issues & it looks like you guys were right. A couple of leaking caps on the PSU board.

    [​IMG]

    [​IMG]

    [​IMG]
     
  5. macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #5
    Those black things with the yellow tops aren't capacitors, those are transformers. They're supposed to have that gunk on them. They extremely rarely go bad. The only ones that I know of going bad under normal use are the flyback ones.
     
  6. thread starter macrumors 68000

    Goftrey

    Joined:
    May 20, 2011
    Location:
    Wales, UK
    #6
    Oh! Well that's good news I guess.

    If it's not caps then what on earth could the issue be?
     
  7. macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #7
    I would suggest replacing the power supply with a known good one or even all of its capacitors. Just make sure you get the right revision power supply. The tray loaders had two different power supply revisions.
     
  8. thread starter macrumors 68000

    Goftrey

    Joined:
    May 20, 2011
    Location:
    Wales, UK
    #8
    Just had a quick look around & it doesn't seem economical to buy the power supply as a part when you go & buy a fully working one for the same price or even cheaper.

    Guess I'll do something funky with it in the future. Thanks for the help :)
     
  9. macrumors 68000

    MisterKeeks

    Joined:
    Nov 15, 2012
    #9
    If you have a multimeter handy I would try seeing if you can get any power out of the power supply.

    You might be able to get a very low wattage power supply and use it instead. I believe that the G3s had an 80 watt PSU.
     

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