iMac G5 intermittent shut down

Discussion in 'PowerPC Macs' started by fb-guy, Nov 13, 2006.

  1. fb-guy macrumors newbie

    Nov 13, 2006
    I have one of the 20" iMac G5's covered by the warranty extension for the intermittent shutdown problem. The problem is that I am out of the country, and where I am has very unreliable Apple service. It would be gone for weeks and weeks. I am considering flying back home to get my computer repaired. The computer shuts down multiple times a day without warning.

    What are the chances I can find an AASP in the DC area who can do the repair in a day or two. I have read that the repair is only a power supply swap and can be done in 15 minutes. What do y'all think?

    My other option is to just buy a new computer and worry about repairing this one in a year or two, which is a $2,000 hassle.

    Anybody have any ideas?
  2. eji macrumors 6502


    Jun 8, 2004
    Inland Empire
  3. eji macrumors 6502


    Jun 8, 2004
    Inland Empire
    Actually, I just stumbled across the repair extension page (it was news to me) and the corresponding thread on Apple Support. Based on some of the posts there, it looks like you might be able to get the EMC mailed to you so you can do it yourself.

    Looks like my iMac falls into the faulty EMC range, so I'm surprised that the corrupted .plist files were at the root of my shutdowns, but the computer has been running for days at a time without a hitch ever since. If it does start playing up again, I guess I'm off to the nearest service center.
  4. fb-guy thread starter macrumors newbie

    Nov 13, 2006
    Very helpful. Thanks. I will try both; it would be great to do the repair here. I took the back off yesterday, and it's an easy replacemnt.
    Thanks again.
  5. TGal macrumors newbie

    Jul 24, 2008
    Intermittent Power iMac G5 EMC-2008

    Hello All,

    I found an effected EMC # of 2056 but it was on the Apple Australia website. Can anyone tell me if this number is covered under warranty for a power supply issue? I have had problems with my system randomly shutting down. This morning I turned it on twice and each time it cycled up and then shut down. Can you please tell me where to go on to find out if my system is warranted for this problem or not? As you can see I don't have a lot of experience fixing computer issues.

    Thanks for your help,
    Terri :confused:
  6. jimoase macrumors member

    Apr 3, 2007
    Me too .......

    I too have a iMac G5 exhibiting random shut down problems. I know this machine to be past warranty so I am looking for either a cheap fix or a trash can.

    So far I found that unplugging the power, waiting 10 seconds, holding the power button in and then plugging in the power, then pressing the power button once as instructed by Apple works but not permanently. Then going to Library/preferences/systemconfiguration/ and tossing it, then do the power plug thing again and then checking the energy settings seems to have worked for a day so far.

    All this indicates the problem has to with PowerManagement. There are several blogs talking about replacing the power supply and main logic at the same time to fix the problem. Apple has used this solution for a couple of years.

    Getting Apple to pay is what would really impress me. Looks like a design error, acts like a design error, Apple has treated it like a design error, must be a design error... I am hoping Apple steps up to the plate and does the right thing, treat this as a design error that does not heal with time.

  7. TGal macrumors newbie

    Jul 24, 2008
    What a bummer

    Hey Jimoase,

    Thanks for the info. Doesn't sound very promising but I will try the powering method that Apple recommended. Will also dump the .plist item.

    Thanks again for the help,
  8. Macky-Mac macrumors 68030


    May 18, 2004
    here's the Apple support page for this issue; G5 iMac repair extension

    I had this come up a couple of months ago and was able to get it fixed for free. Under the repair extension program, you have up to 3 years from the date of purchase to get it fixed at Apple's expense.
  9. wlessard macrumors newbie

    Sep 24, 2007
    Holy moly!!! This is insane... it seems to have worked for me! We just watched all of Iron Man and I installed a huge update to Mac OSX. No sudden shutdowns yet. This iMac G5 used to last at most an hour.

    I was really upset because it looked like the machine was done. Now it looks like I'm back in business. If this has fixed the issue I'm going to set up a maintenance routine to remove the file on a regular basis.

    Thanks so much.
  10. duaneellison macrumors newbie

    Sep 5, 2010
    Wow, I think this might have just fixed my iMac G5 20" problem I've been having. It would just power off without warning. I've been trying to figure out what to do with this thing for a while and was researching parts and such when I ran across this thread. It's been a couple hours so far and it's still running so it still might fail but this is much longer than the 4 - 6 minutes I would get before.

    I'm REALLY glad that I found this especially before I started trying to swap parts.


  11. res259, Feb 19, 2011
    Last edited by a moderator: Feb 19, 2011

    res259 Guest

    Hi All,

    Brand new to this site, but felt compelled to post based upon this thread. I've got an iMac G5 20" ALS that has had this same shutdown problem since I bought it about six years ago.

    The machine runs fine for about 18 months then starts degrading so that shutdowns happen faster and faster.

    This is a very tricky problem as Apple has replaced my logic board and power supply a couple times over but with no luck. Moreover, though they've made certain allowances, they keep pointing out that my machine falls slightly outside the serial number range for the repair extension program and so can't have the fatal flaw that the other units seem to have . . . even though it does. Gotta love corporate America.

    I would contend however that different machines have different problems and that's confusing folks.

    For instance, one of the theories has been that a number of the units have bad capacitors, and this seems to be confirmed by articles such as this one . . .

    Still, since this last time I had a failure, I was outside warranty, I decided to remove the back and see what I could figure out on my own.

    First off, interesting to note that while the computer seemed completely dead by now, jumping the power button contacts with a paper clip hundreds of times, finally got the machine to come back on again. (This alone may be misleading a lot of users AND repair techs; they think they're dealing with a completely dead machine when they're really not.)

    Despite this small victory, the machine would still shut down spontaneously without following any kind of a predictable pattern.

    I did notice that it would shut down more quickly when performing processor-intensive tasks, like playing video.

    This led me to suspect a heat management issue (in keeping with the power management concerns outlined in this thread)

    Leaving the back off and placing ice packs against the power supply and processor seemed to help improve performance initially, but even then the machine behaved erratically.

    I also noticed that unplugging the unit for 10-15 seconds and/or resetting the NVRAM as described helped some.

    Finally though I found that if threw out my entire System Configuration Folder from the Preference file in the Root Library AND then reset my screen saver (didn't matter to what, just so long as I forced the computer to write something to the new preferences file) the computer started running stably again. Note that the the above tip suggests simply deleting the PowerManagement preference, but I took it a step further.

    Unfortunately, I wasn't rigorous enough in my testing. Success may have been because I threw out the old file, or because I overwrote the new preference file, or because I rebooted, or any combination thereof. It's worth noting however that simply removing the file wasn't enough to get the machine running predictably.

    Hope this helps others. I apologize for the long story!
  12. duaneellison, Feb 21, 2011
    Last edited: Feb 21, 2011

    duaneellison macrumors newbie

    Sep 5, 2010
    You know I had completely forgotten about this thread until I received the new message subscription.

    My previous attempts where I said that it was working was very short lived. The iMac G5 has been sitting in the garage for months now because I was utterly frustrated with it.

    So with this "new" information I pulled it down again and decided to give it another go.

    First thing, like a moron I didn't just turn it back on and let it run to see what would happen. Instead I immediately booted in single user mode and went about mounting the drive and tossing (rm -r /Library/Preferences/SystemConfiguration) and then rebooting the machine.

    So it came up and appears to be operating. I've started system updater and it has spent the last hour or so downloading updates from the web while my son is playing around with pages. I'm not sure if this is going to work but it sure would be nice if it does!

    UPDATE: So it ran fine for about three hours maybe four. It finished all the system updates which took most of that time. It rebooted and then did it's thing applying the updates... Then it died... To get it to restart I had to take the back of and push the little buttons - I didn't look them up or anything. Once it started working again I did the single user mode and trashed the SystemConfiguration folder again... I'm letting it sit and run again to see what happens... All in all pretty darn frustrating - but maybe something clobbered the SystemConfiguration folder during the updates...

    More to follow once I get some more time on the machine...

    UPDATE #2: It just died again... So I'm not sure what to think... I suppose it's just given up the ghost...

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