iMac G5 PowerPC running SUPER hot

Discussion in 'PowerPC Macs' started by c0bracommander, Feb 17, 2010.

  1. macrumors member

    Nov 5, 2008
    I'm not sure what the issue is, but my 20" iMac G5 PowerPC is running so hot and smelling very "electrical".

    I took the case off the back of it, and it seems where the G5 metal portion (not sure what it's called) is the source of all the heat. I can't really put my finger on it for more than a couple seconds because it's so hot.

    Some recent things I've done was lube the fan, and replaced the RAM. I got the RAM per the Crucial ram identifier program that runs on the computer and lets you know which type to purchase.

    The first batch Crucial sent was giving me about 5 kernel panics within the first week I got it. I sent that back. I received the new one, and it seemed to be no problem in terms of performance at least up until today.

    I'm not sure what this can be related to. All I really did was while the RAM was out was dust off the internals and clean it up. I don't think I really messed with anything, which makes me think this might be a RAM issue.

    Until I changed the RAM everything was fine with the computer with no prior problems.
  2. macrumors 68000

    Feb 13, 2009
    United Kingdom
    Try installing iStat Menus (cant remember the link) or iStat Pro to see what your CPU temperature is like - this may help which part is overheating (and also by how much). :)
  3. thread starter macrumors member

    Nov 5, 2008

    Cool program. Ok, so far, as I'm typing this with Safari being the only app open (along with this istat menu program) the CPU temperature is 132 Degrees Fahrenheit. Is that a little excessive?
  4. macrumors 68040


    Sep 17, 2009
    132 fahrenheit are 55 celsius , a bit warm but the iMacs run a bit warm
    if its dust free inside the 55 celsius or 132 fahrenheit would not concern me
    i guess you got a heated room too , is it close to a heater?
    because it could make a difference too as the cooler the room temp the cooler the imac is running

    you have to remember all there is to get cool air in are these tiny vents at the bottom and this little slit at the top to get the hot air out
  5. macrumors 68020


    Nov 5, 2009
    132 f is ice cold for the G5. My G5 basically idled at 164 f, and never had problems.
  6. macrumors 68040


    Sep 17, 2009
  7. thread starter macrumors member

    Nov 5, 2008
    Ok, thanks guys. I will definitely keep an eye out. I wish I had this program installed the other day when this thing was burning up, practically.

    This program is sweet though. Thanks for recommending it! I've installed it on my MBP as well.
  8. thread starter macrumors member

    Nov 5, 2008
    Hi all,

    Another update. Same thing happened tonight. Both times it has happened, the computer has gone to sleep and it hasn't awoken... no ambient light sensor either.

    The temperature gauge (although a nice feature), probably won't help, as it seems this issue occurs when it's in a "Dead sleep" and I can't get on to see what the current temp was.

    After removing the case again, the same spot was really hot and I could smell that fried electronic scent.

    I'm thinking it may be the RAM, but I'm not sure how to find out? It's too old to be taken into an Apple Store (or not worth it, I think) without getting ripped off or quoted some insanely steep price to fix it.

    Any other ideas?
  9. macrumors G4


    Sep 7, 2006
    In the velcro closure of America's Hat
  10. thread starter macrumors member

    Nov 5, 2008
  11. macrumors 6502a

    Jan 19, 2008
    when you say sleep - do you mean sleep or a hard shutdown? ie when you get it back up and running does it resume from sleep or go through a boot?

    can you post a pic of the spot that was hot?

    i'm wondering if you have a psu problem - where it overheats and eventually the machine shuts down immediately and with no warning at all.

    thats what happened to mine.
  12. macrumors 68040


    Sep 17, 2009
    if it is a 20" 1.8ghz model it could have bad capacitors ..which would explain the smell and sudden shutdowns /sleepproblems and other issues
    the 2.0ghz models are not known for bad capacitors
  13. thread starter macrumors member

    Nov 5, 2008
    Damn. I thought this issue was solved after following the instructions for resetting the SMU the first way listed on Apple's site.

    Today, the same thing happened when I came back to my computer. It's like it goes to sleep and when I moved the mouse/click it/or type on the keyboard, nothing happens. I can hear it on, like the fan is on a dull roar but the ambient light sensor is off and I can't even press and hold the power button to turn it off in the back. I ended up just unplugging it.

    Here is a pic of where it gets SUPER hot:


    And yes, it is, unfortunately, the 1.8ghz model.

    I tried the second option for resetting the SMU. We'll see if it helps at all.
  14. macrumors 68040


    Sep 17, 2009
    and the metal thing which has G5 written on is the heatsink of the processor

    if you got it open have a close look at all capacitors you can find in there , if they are bulged or leaking or just do not look right
  15. macrumors 6502a

    Jan 19, 2008
    that part will be hot so its likely not significant.

    have a look at the events on console and see if there's anything unusual going on at the time it goes to sleep or just before.

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