imac regularly enters sleep mode when browsing web

Discussion in 'Mac Basics and Help' started by dean1234, Oct 1, 2011.

  1. dean1234 macrumors newbie

    Oct 1, 2011
    Hi, I've had my imac G5 (power PC) for about 3 years now and it's run perfectly without any issues. I've been updating the operating system frequently and worked with programs such as Final Cut Pro Studio without any issues.

    Recently I upgraded my mac to leopard (10.5.8) and for the first few weeks it's ran fine, however the last week or so my computer has been entering sleep mode every 10-20 minutes when I'm on the internet. I've tried using both Safari and Firefox but both have had the same issue. I've tried emptying my cache and deleting un-used plug-ins, taking out and putting back in my extra RAM, as well as loads of other advice gathered from trawling the forums, but the issue still remains.

    From viewing my activity monitor I can see that when using safari/firefox my CPU usage rockets between 70%-100% and it's usually when it hits 100% that my computer goes into sleep mode. I've tried updating Flash because my CPU usage hits 100% when i'm on a website with flash apps or adverts but I'm told my system doesn't support the update. Also if I have a few tabs open or programs my computer shuts down

    Is there anything I can do to resolve this issue? is it related to updating to Leopard as I never has the issue before? here's a few extra details about my computer:

    Model Name: iMac G5
    Model Identifier: PowerMac12,1
    Processor Name: PowerPC G5 (3.1)
    Processor Speed: 2.1 GHz
    Number Of CPUs: 1
    L2 Cache (per CPU): 512 KB
    Memory: 1.5 GB
    Bus Speed: 700 MHz
    Boot ROM Version: 5.2.6f1

    any help would be greatly appreciated

  2. dean1234 thread starter macrumors newbie

    Oct 1, 2011
    can anyone help with this issue?

    I've just found that it also enters sleep mode when on FCP now too

  3. whooleytoo macrumors 604


    Aug 2, 2002
    Cork, Ireland.
    Strange.. could it be an overheating issue? There are apps you can download which will tell you the temperatures of the various components.
  4. snberk103 macrumors 603

    Oct 22, 2007
    An Island in the Salish Sea
    Yeah, check the temps like whooleytoo suggested. Also check your Preferences, under the energy settings. Make sure the system isn't merely going to sleep after X minutes of idle use (such as reading a page). Also check to make sure you don't have a hot-corner set to send the system to sleep - also Preferences - Expose.

    Good Luck
  5. dean1234 thread starter macrumors newbie

    Oct 1, 2011
    Hi thanks for the response. no it's not a heating issue I downloaded 'istat pro' which reads my computer is running between 50-70 degrees. Also when I touch the back it isnt as hot as it used to get before the sleep issue.
  6. dean1234 thread starter macrumors newbie

    Oct 1, 2011
    Hi, after looking even deeper into the issue I think you may be right that it's connected with the heat my CPU is running at. when my CPU usage hits above 70% the temperature reaches around 75 degrees (Celsius i think). My CPU fans are also always running at 3600rpm. Am I right in thinking when visiting websites using flash or programs such as FCP my temperature will increase? Is there anyway I can bring this down either downloading software, cleaning out the inside of the computer or fixing any other issues?

    As I'm using a g5 powerPC there are many compatibility issues with a lot of the programs

    thanks again
  7. eljanitor, Oct 3, 2011
    Last edited: Oct 4, 2011

    eljanitor macrumors 6502


    Feb 10, 2011
    I have a 1st gen iMac G5, it sits in the direct sunlight all afternoon in 85° - 100° F ambient temps just when its off and not in use. It does get high fans while running flash applications, it usually has high fans when its on, because its always being pushed so hard by its current owner. Yet that little thing goes and goes! Some people use SMC fan controller to manage cooling.

    The iMac G5 was notorious for overheating issues. They would blow capacitors on the logic board, and also in the OEM 1st generation power supply. The power supplies did sometimes burn the logic board. Ive worked on so many G5 iMacs over the years I've seen everything they do, and here's my advice. If you live in a dusty place, open the case once every 3- 6 months and with a can of compressed air blow out the CPU heat sink, and all 3 exhaust fans, and air passageways. All that dust comes out and it runs cooler.

    Now if grey flakes come out when u blow air in there with the dust STOP! because the thermal paste is coming out with the air!!!! If this happens you need to re-seat the heat sink to the CPU with fresh heat sink paste. or it will overheat and cook the CPU. This happens with iMac G5's too over time, the thermal paste gets funky and dries up and flakes off.

    With your sleep issue, it looks like it goes to sleep because they are designed to go into a low power state when they get too hot to protect the CPU and the fans are supposed to come on and cool it down. When that happens you should make sure that.

    1) All the thermal sensors are working properly and connected.

    2) Make sure all the fans are working properly. this a great tool to check that all the fans are working etc.

    3) Make sure the heat sink and CPU are properly seated for cooling and the heat sink paste hasn't started coming off.

    I only worry when I start one up and it sounds like a commercial jet taxing down a runway with all the fans on full blast with no image on the display. Then usually it's seen better days and it's time to buy a new mac.
  8. dean1234 thread starter macrumors newbie

    Oct 1, 2011
    Thanks for your response. yeah my house does have a dust issue so that could be the cause of the issue. I'll clean the inside and post up the results. All the fans are working fine too so again may just be a clean issue

    cheers :)

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