iMac G5 Random Shutdowns/Super loud fan noise!

Discussion in 'PowerPC Macs' started by breakdown77, Jul 29, 2009.

  1. breakdown77 macrumors newbie

    Jul 29, 2009
    I have a problem... I use very processor heavy programs on my iMac G5 and up until about a year ago, I was getting along ok. Here's the gist of it:

    1) World of Warcraft/ProTools etc. Prolonged use over many hours eventually caused my imac's fan noise to be unbearable. Even worse, my imac began randomly shutting down almost predictably during high processor use.

    2) Was taken to an apple store (while in warranty) and only thing said was that it needed a new logic board. No explanation what actually happened to it. Logic board replaced. Few months later, it's happening again.

    3) I am now outside an apple warranty and it will cost me $400+ to get it repaired. It is functional for regular internet use, but on sites like youtube, after a few videos it will likely shut down.

    I have opened up my computer several times to inspect the capacitors, but they all look like new. I realize overuse is probably the problem, but if there is a fix I can do myself, I'd at least like to try. The problem is that I have no idea what to do :) I hate hearing "needs a new logic board" instead of "this part ____ needs to be replaced/fixed"

    Any help is greatly appreciated!

    Specs: iMac G5 17" 2.0ghz generation right before isight macs.
  2. geoffreak macrumors 68020


    Feb 8, 2008
    Your computer is overheating. This is likely due to dust buildup or clogged vents.

    You need to open up your computer and clean it out before "this part logic board needs to be replaced/fixed"
  3. breakdown77 thread starter macrumors newbie

    Jul 29, 2009
    I hate to ask but what's the best way to do this and where exactly should i start? Wondering if i have to get under the big G5 processor cover to.
  4. geoffreak macrumors 68020


    Feb 8, 2008
    Even though you are out of warranty, you can try stopping by the Apple store and see if they will blow out the dust for you. If you are really nice about it, they might lend a hand.
  5. breakdown77 thread starter macrumors newbie

    Jul 29, 2009
    Just downloaded a temperature widget and found some startling numbers:

    161.5°F CPU and 115.7°F Hard drive

    That is minimal use! I have only safari open at this website!

    Even at that high of a temperature the fans are pretty quiet... watch me go to youtube and insta-random shutdown! I took out the lower fan box and gave it a good cleaning though it looked like it was relatively dust free.

    I'm pondering an aftermarket fan mod right about now.

    Just measured a 179.2°F while at youtube.
  6. MacHappytjg macrumors 65816

    Mar 24, 2008
    Did you get the dust out of the processor duct as well, alot is usually clogged in there.
  7. armoguy94 macrumors 6502

    Nov 9, 2007
    You NEED to clean the dust inside before you use it again for it to burn more.
  8. breakdown77 thread starter macrumors newbie

    Jul 29, 2009
    Ugh... Ok so I spent about 20 minutes cleaning dust out of every crevice of my imac. I bought a dust blaster air can and carefully blasted out the fans and inside the processor housing. I did A LOT of blasting.

    I'd be lying if I said it didn't make a difference, because it did. My iMac is noticeably cooler on normal tasks. High 140s°F (about 65°C). This still seems way too hot for me. The fans did quiet down a great deal though.

    It was too quiet so I ran 2 youtube vids and opened garage band. It jumped up to the 175ish°F again (80+°C).

    Also, I experimented with the processor setting (Auto, Highest, Reduced). I expect Reduced would be ok for normal internet use, but if I ever dare play WoW on this comp again it will have to be set on highest or auto. And I'd most likely have to add an aftermarket fan :p

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