iMac G5 20" with loud fan like noise...

Discussion in 'PowerPC Macs' started by mrrhtuner, Jan 3, 2016.

  1. mrrhtuner macrumors newbie

    Apr 14, 2012
    Hello everyone,

    I've aquired a iMac G5 20" unit with the powerpc processor a bunch of months ago. It sat in my home office on the floor as I was told it's dead and my plans were to eventually take a look at it.

    Well with the help of a friend last night, we turned it on and to my works!

    The problem though? the unit sounds like it has a bad fan in there somewhere.

    Before we begin, I have done the capacitor reset (power off/hold power button, etc...) and it has not helped.

    I am unable to exactly locate the sound but it sounds like it's coming from the right side of the pc, but I am not exactly sure on that.

    I did my best to record a short clip of the noise in hopes that somebody has heard it before and can give me an idea on what to look for.

    Doing a bit of googling around, I did see that some of these units had power supply issues. This one seems fine and I don't think the noise is from a PSU.

    Listen here if you can and I'd appreciate any feedback.

    Thank you kindly for your help
  2. Dr. Freeman macrumors member

    Dr. Freeman

    May 1, 2012
    You'll definately gonna have to open it up and clean up the dust, these iMacs tend to get ridiculously hot and most of the time they damage stuff like the screen and the motherboard.

    Open it up and change the CPU's thermal paste, you can buy some at your local computer shop.
  3. mrrhtuner thread starter macrumors newbie

    Apr 14, 2012
    Thanks Mr.Freeman.

    I found the ifixit guide and started taking it apart.

    With my luck, I broke a bit of the connector for the IR/Camera cable

    Just my luck :(
  4. mrrhtuner thread starter macrumors newbie

    Apr 14, 2012
    So here is a small update.

    I'm on the hunt for the cable but apparently I cannot see the macrumors marketplace until I hit 250 posts. oh well.

    I continued to remove the logic board and here is what I've found:

    Capacitor #1:

    Capacitor #2:

    One of the bulging capacitors I can see on the other end the pins.

    But one of the other bad capacitors are covered under this heatsink, which I presume is for the powerpc processor?


    Does anybody have that IR/Camera cable by any chance?

  5. appleish19 macrumors regular


    Dec 4, 2014
    I have the 17 inch iMac isight model. I'm going to have to open it up as well. I have a serial number one where the capacitors aren't a problem though. It runs pretty hot but I'm going to try to do the thermal paste as well. Any recommendations for opening up without the damaging the iSight?
  6. mrrhtuner thread starter macrumors newbie

    Apr 14, 2012

    Luckly I found a local 20" iSight imac G5 for sale last night for $20.00

    It powers on but has a HDD failure.

    I used the iFixit guide to follow the process of removing the heatsink fan. That cable, the one I broke was the only difficulty/snag I ran into.

    If you have the 17" iSight, I think you have this model.

    Anywho, don't try to pry that connector out with a screwdriver. That's what I did. Never had an issue doing so before but this one that I broke for the IR/Camera is too long (the plastic connector). Trying on it causes flex and cracking.

    Gather as many cables as you can and pull in the opposite direction of how it's inserted.
  7. mrrhtuner thread starter macrumors newbie

    Apr 14, 2012
    This may or may not help you but I made a quick video about how to remove the logic board without removing the IR/Camera cable. If I would have done this the first time around, I would have saved myself from breaking the cable.

    Check this out:

  8. mrrhtuner thread starter macrumors newbie

    Apr 14, 2012
    Well small update,

    Lucky for me being able to find the exact same 20" imac iSight model locally for dirt cheap, I was able to compare both internal components and choose the better of the two.

    First I used the most recent motherboard(based on production date) and it like the other, had swollen capacitors.

    I ordered capacitors from and once they arrived, I started to learn something I've never really done much, soldering.

    I figured out how to solder/transfer heat from the iron to the existing solder and off to town I went working on the motherboard.

    I replaced all the capacitors and started to assemble the unit again. The better of the two PSU does have a capacitor starting to swell but I'll use it for now and if it '***** the bed', I will give it a go at replacing it. I did put new heatsink compound on the processor chips since I had to remove all the heatsinks.

    The assembly is almost complete. I hooked up the LCD panel to the logic board/power connections and fired it up. To my dismay, the unit booted up just fine.

    Now my task is to format this drive and a fresh install and watch the temperatures and see how the computer performs.

    I left it on last night with a few temp monitoring programs and when I woke up 7 hours later, the unit was still on and had the programs up restarts.

    Here is a screenshot of the temps last night at around 11pm, shortly after it was powered on.


    I've noticed this morning the temps were a bit higher this morning:


    Will need to work on it a bit more and find out if anything is getting too hot for the PC's liking
  9. mrrhtuner thread starter macrumors newbie

    Apr 14, 2012
    So one thing I've just noticed in my original video uptop, the bottom right corner, white LED light does not illuminate.

    Some of the iMac's i've seen online have it on, indicating the unit is turned on.

    Would mine be broken or just somehow disabled?
  10. andyt3 macrumors member

    Feb 2, 2016
    Western MA
    For what it's worth, I have a 17" non iSight model. My white LED is only on when the unit is sleeping. It fades in and out. Otherwise, it's not on at all.

    I was also wondering the same thing, if there was a setting somewhere so it would be on when the unit was powered on. So far, I haven't found anything.
  11. d-oost macrumors 6502a

    Jan 10, 2016
    It is supposed to go on at boot, then fade out right before the screen kicks on. It will "breathe", like on other Macs, when in sleep mode. This is the same for the iMac G4 and eMac.
  12. andyt3 macrumors member

    Feb 2, 2016
    Western MA
  13. mrrhtuner thread starter macrumors newbie

    Apr 14, 2012

    Great, thank you for the clarification.

    The iMac's been running great. I don't have a whole lot of use for it. I did score a 2009 MacPro yesterday so I'll be dabbling with that a bit more :)

Share This Page

12 January 3, 2016