12 Replies Latest reply: Jan 11, 2008 12:04 AM by deo160
thepretzel1203 Level 1 Level 1 (0 points)
Hey all,

I recently purchased the 20" 2.4 GHz and have been experiencing random power failures. Right in the middle of typing an essay or watching a movie, my computer turns off unexpectedly. Has anyone else experienced this problem or know what might be going on? The only things I could think of are static buildup/discharge in the power supply or overheating...

Thanks!

2.4 GHz 20" Imac, Mac OS X (10.5)
  • yellowstar76 Level 1 Level 1 (10 points)
    i'm having this problem too, but with my 17" macbook pro. it's only when i'm running on my battery, but my meter says i have an hour or so left and all of the sudden, my computer just loses power. no warning. no "you're running on reserve battery power" notice. no shut down process. nothing. just turns off. and then it won't turn on until i've plugged back in, so it's obviously a battery-related issue....but just not sure how to deal with it.

    it just started doing this in the last 2-3 weeks. anyone know what's going on and how it can be fixed? i have made no changes to my preferences or system besides updates.

    Message was edited by: yellowstar76
  • Euripides Level 1 Level 1 (25 points)
    I have had this problem on a 17" iMac (early 2006) and fixed it. It is most likely unrelated to the new Aluminum iMacs. The problem was a loose DC logic board connection that over time had loosened and caused the machine to randomly shut down. My long trial-and-error testing saga is as linked, I wouldn't recommended reading it though unless you're bored or have a lot of spare time. Make sure your RAM is seated well, reset SMC (unplug all cables, even power, for 15 seconds), reset PRAM (apple-option-P-R) on startup.

    http://discussions.apple.com/thread.jspa?threadID=1088454&tstart=0

    I came across this app, not sure what machines it supports but it is a universal binary, so methinks it will work on any Intel Mac.

    http://www.bresink.com/osx/SystemLoad.html

    Good luck!
  • Priam Level 1 Level 1 (0 points)
    Exact same thing happened to me.
    Apple declared the defective machine DOA and replaced it with a new one.

    Try the PRAM and SMC resetting options described on the main support pages. If those procedures don't solve it, let Apple Support know you tried, and the call should go quickly.

    One caution is to de-authorize each piece of third party software with the individual manufacturers before wiping your machine. I failed to do that, and had to explain why I needed an allowance for duplicate installation several times.
  • iRocket Level 1 Level 1 (30 points)
    I have a iMac G5 (purchased 5/05) and I never had an issue with it other than having to manually connect to my home network) Recently (last week) I called Apple Support about my network issue and we did a commandoption+PR during powerup. This is the first time it was ever performed. Since then My iMac turns off (completely) randomly. It doesnt matter if I am surfing the web, watching a movie, or the machine is idle doing nothing, and BAM no power. I'm glad I bought the 3 year Apple iCare package, because it seems that Apple knows in about 3 years, the machines begin failing.

    I performed the SMC procedure about 30 minutes ago. I will update this post if I no longer have the loss of power issue again.
  • quantumsoup Level 1 Level 1 (0 points)
    I have the exact problem of Rnadom Shut Downs with my white iMac 20" Intel 2.0 GHz. I didn't buy the extended warranty since nothing much else went wrong in my 25+ years as an Apple user - and the Murphy's Law kicked in about a month after it ran out of the Apple 12-month warranty.

    After the RSD, the iMac wont startup for a time (this ranges from thirty minutes to a whole day) and when it does, it blacks out after about 4/5 minutes and I'm not even doing anything intensive during those uptimes - maybe writing an email or just browsing.

    I'm now looking at disassembly to take a look at the logic board connections as suggested by Euripides
  • George Peters Level 4 Level 4 (3,165 points)
    Since you have an iMac G5 your case in particular is different than the problems that some of the Intel iMacs are having. It is a known issue that Apple has an Extended Repair program for regardless if you have Apple Care or not.

    http://docs.info.apple.com/article.html?artnum=302181
  • iRocket Level 1 Level 1 (30 points)
    well...I finally couldn't log on to inform anyone that my attempts at an SMC reset and an appleoption+RP didn't solve my problem. I also should note that the display would show snowy specs in the blackest areas of the display like static specs. Well, since I finally couldn't power up for more than 10 secons (as it was degrading fast) I took the iMac to the apple store, got a new powier supply for it and OMG it works!! So I am back in business.

    Solution for iMac power issue and Display snow : Power Supply

    Hope this helps even the intel mac users to some degree.
  • cavenewt Level 2 Level 2 (345 points)
    yellowstar76 wrote:
    i'm having this problem too, but with my 17" macbook pro. it's only when i'm running on my battery, but my meter says i have an hour or so left and all of the sudden, my computer just loses power. no warning.


    Your laptop has entirely different power circuitry. You should post in the MacBook Pro forum, not the iMac forum. Your issue may be addressed by resetting the power controller, or getting a new battery, or something that is MBP-specific.
  • cavenewt Level 2 Level 2 (345 points)
    iRocket wrote:
    I have a iMac G5 (purchased 5/05) and I never had an issue with it other than having to manually connect to my home network) Recently (last week) I called Apple Support about my network issue and we did a commandoption+PR during powerup. This is the first time it was ever performed. Since then My iMac turns off (completely) randomly. It doesnt matter if I am surfing the web, watching a movie, or the machine is idle doing nothing, and BAM no power. I'm glad I bought the 3 year Apple iCare package, because it seems that Apple knows in about 3 years, the machines begin failing.

    I performed the SMC procedure about 30 minutes ago. I will update this post if I no longer have the loss of power issue again.


    That vintage of iMac (and eMac) had a problem with bad capacitors (the problem hit other manufactureres than Apple, too.) If you open up the case and look at the logic board, see if any capacitors (the little barrel-shaped doodahs) are swollen or leaking brown fuzz. If so, Apple had an extended repair program for that, although you're lucky you have Applecare. If you're not comfortable opening the computer (that model is easy, just 3 torx screws along the bottom edge, though it's a little tricky getting the cover back on when you're done), definitely take it to a Mac tech ASAP, as this gets worse with time.

    Message was edited by: cavenewt
  • iRocket Level 1 Level 1 (30 points)
    Please see: "Re: Random power failure / shutdown?
    Posted: Dec 23, 2007 4:12 PM in response to: thepretzel1203"

    My Particular iMac G5 already had the new capacitors installed to remedy the bad line of capacitors apple bought from their vendor. My issue was solved (snow and power issues) by simply replacing the power supply (thankfully under the apple protection program) and cost me nothing.
  • deo160 Level 1 Level 1 (0 points)
    I too am getting this with the intel mac and it is also close to end of warranty, mine does it in Windoze XP and in Ubuntu as well so absolutely Hardware. It is now in with a Mac Tech in Aldridge to take a look see, will let you know, when they let me
  • deo160 Level 1 Level 1 (0 points)
    the mac tech replaced the power supply unit and I am now the proud owner of a lovely fixed Mac. All under warranty