Gibbilicious

Hi,

This just happened to my iMac G5 also and came across this site when googling to see if I could figure out what happened.

Anyway, I've come to the same conclusion as you, it happened to me just as someone else in my house was fiddling with the fuse box outside.

So yes, it seems it is a symptom of an external power issue.

Cheers,
Maskil

This is happening to me also. Just seems to shut of when it feels like it. Sometimes, many times in a row.
Did the battery replacement resolve it for you? I took my Mac to the Apple Store but of course it worked fine for them. Brought it home and it started up again. What do you mean by "it seems it is a symptom of an external power issue."

Yes, the battery replacement on the external Uninterruptible Power Supply did do the trick - I have never again seen any kind of unexplained shutdown since then.

When I said "it seems to be a symptom of an external power issue" I mean that this particular error code is left in the Mac's logs when the power coming into the Mac from "outside" causes the Mac to shut down. That is, it has nothing to do with the Mac's power supply, main logic board, etc., so the Mac doesn't need a repair, and really there's nothing that the Apple folks can do to help. Rather, you need to look at "external" issues, like perhaps your electrical outlet is on an overloaded circuit, or your neighborhood experienced a brownout or power outage, or your power strip is failing, or (as in my case) your UPS is failing. If you do NOT have a quality UPS on your Mac, and you're seeing this error, I would highly recommend getting one - I would bet dollars to doughnuts that your problem with unexplained shutdowns will disappear.

Hope this helps explain things!

    ..Chris..

Hi, I got home and of course, my computer shut itself down during the day. I restarted and it shut of about 10 minutes laster. I checked the log and I found: 'Dec 7 17:42:54 localhost kernel[0]: AppleSMU -- shutdown cause = -122.' Is this an external power problem?

When I did a live chat with Apple the other night, they had me do an SMU where I disconnected everything, held the power button while I reattached the power cord to the back of the Mac and then restart.

In doing a bit of searching, it looks like the ApplePMU (which I have) and the AppleSMU (which you have) are basically the same thing (Apple's proprietary power management module). Early G5's (like mine) used the ApplePMU; late 2004 and beyond G5's reportedly use the AppleSMU.

Since you have a recently purchased G5, and the error code (-122) is the same, I think it's very likely that it's the same problem. In other words, yes, it's most likely an external power problem.

Beg, borrow or steal a UPS from a friend, if you can, and try running the computer on it at your home, and see if the problem goes away. I'm betting that it will, and you can then go buy a UPS with a clear conscience.

I don't know why Apple reps don't know about that error code. It seems that Apple has made their entire implementation of the ApplePMU/AppleSMU proprietary to the point that even their own tech reps don't know what it means, and they make you go through the whole "resetting the SMU" thing, which is worthless if it's an external power problem.

If you get to give a UPS try and it solves the problem, please do me a favor and post back here to confirm!

Good luck, and let me know how it goes.

Cheers!

    ..Chris..

Hello, I have this problem as well! i am also getting an SMU code = -110 and SMU code =1. Does anyone get these codes or have more insight? Apple Chat had me reset the SMU and delete powermanagement.plist and preferences.plist from the Macintosh HD>Library>System config folder. I will try the UPS idea tonight. I also noticed that the power cord had worked itelsf out so that the disc portion was not flush with the back of the mac. BTW - i just got this iMac, 20" iSight a month ago.
Thanks for you time and help!
Julito

Hmmm - both the "-110" code and the "1" code don't seem to come up with any Google results. The "-122" code that I saw on my machine turned out to be a power quality issue, which was solved with the addition of an external UPS system, but your problem sounds a bit more involved. Sorry to hear your new Mac is giving your problems. I continue to search for an "official" list of Apple power manager result codes; if I come across it, I'll certainly post it here. But it sounds like you may be at the mercy of Apple support for the time being. :-(

    ..Chris..

Julito,

I get the SMU code when I do a normal shut down and restart. I get the 122 code when it shuts off and I restart and go to the console.

Im still having problems but I'll try the delete powermanagement.plist and preferences.plist. By the way, they're in the Mac>Library>Preferences>System Configuration folder.

Brian

I have a G4-400 that showed the same -122 shutdown one year ago.. after many trials, including PMU button on the motherboard, it stopped shutting down.. (I don't remember all details..)
I noticed like you that the -122 is written at restart...
I got a new Power unit, a new UPS... even bought a 1GHz CPU upgrade.
I thought life was beautiful, since 3 days ago where my G4 again restarts to stop at any moment and again shows -122 code. I checked the UPS battery from a PC (damned unitek that don't have software for macs!)... tried w/o the UPS.. same..
of course , will try another UPS but I doubt it is only an external issue ...

Does your G5 work well ? We are a lot of people on this side of the Atlantic meeting similar G4 or G5 shutdowns... why no more noise around this ?

Arvig: Well, in my case, my G5 is still running without a single hitch since the replacement of the external UPS battery.

I still have not found any "official" list of PMU messages, but now that I've had several other readers report in, I'm thinking more strongly than ever that the -122 error is sort of a catch-all error for "miscellaneous problems" or "sudden, unexplained shutdown".

I think that, if you get a -122 error, all you can do is start with the easy and cheap things, and then go on from there if you still have problems. Scary!

..Chris..

Just for reference for others who find this post... I arrived here whilst trying to figure out why my 20" iMac G5 is restarting randomly. I bought a UPS yesterday and have tried two different power cables, so I believe the continued unexpected restarts are because of either:

+ Heat.

It is summer and 31 degrees celcius inside at the moment, and I've heard that iMacs can do a thermal shutdown when they overheat. However, the random restarts are happening when it's a little cooler as well, and it should be within operating temperature.

+ Known component failure

According to http://www.apple.com/au/support/imac/repairextensionprogram/ this iMac from a series with possible video and power problems.

Like Chris, I see SMU entries in system.log:

Dec 30 13:22:53 localhost kernel[0]: AppleSMU -- shutdown cause = -122
Dec 30 13:22:53 localhost kernel[0]: AppleSMU::PMU vers = 0x000d006b, SPU vers = 0x2b, SDB vers = 0x01,

Hi Nathan - thanks for the post. I actually had a PowerBook once that went insane and ran the CPU full-out until it overheated and did an emergency thermal shutdown. I don't remember what the specific SMU or PMU code was, but the log clearly listed in plain text that the PMU had initiated an emergency shutdown due to an overtemp thermal condition.

Hello again - Chris, i followed your advice and got an APC 800 XS series UPS. I've left the iMac on sleeping inbetween cycles for the past 4 days and no unwanted shutdowns! After plugging in the charged UPS, resetting the SMU and deleting the .plist from above - all seems well. I'll keep my fingers crossed.
Thanks for your time and help!
Julito

Just posting to say that I'm glad I found this through Google. I've been having the same shutdown problem with my G5 iMac for about a week now and I've tried everything under the sun to remedy the problem. Right now as of about 10 minutes ago, I've moved the power cord to a dedicated outlet to see if that helps to remedy this. I've already done the SMU reset and deleted the .plist files to no avail. Hopefully this helps some; it's getting terribly frustrating as of late. I'm still covered under Applecare but rather I'd try possible solutions before I result to that.

Randy - glad if this helped; I know it was very frustrating when I first ran into this problem and couldn't find much in the way to explain what was happening, even though I had what looked like a nice exact error code in my system log!

Anyway, please come back and post how things went; whether your Mac is still running great after a week or so (let's hope!), or not, it's still valuable information for the future.

I know that one reader finally did have to get a new logic board and power supply replaced, but several others have had their problems disappear after improving the quality of the AC power going directly into the Mac.

I still think that the "-122" code is a sort of catch-all code for any mysterious sudden failure of power to the main logic board, whether from internal or external reasons, but taking steps to eliminate the easy and cheap problems first can, hopefully, save you from having to deal with Apple Support.

Good luck!

  ..Chris..

Another update - hopefully this problem is finaly fixed. After my UPS purchase, the iMac ran fine for a week - then the same problems showed up again! I took it in the Apple Store (Tysons Corner) and they did two things. First, they replace the main logic board - no repair. Then they replaced the AC to DC power supply and that has since solved my problems. I ran the machine HOT last night by installing iLife 06 and importing video to iMovieHD. After rendering all the letterboxes and other activities the iMac performed "like butta".
If you have warranty or apple protection, i highly suggest bringing in your faulty iMacs before it's too late. Good luck!
Julito

Like the rest of you, I found this site while searching for the cause of my iMac’s baffling and frustrating spontaneous shutdowns. I’ve had the machine just over a month and it worked like a dream up until a week ago. I was experiencing the same symptoms and Console logs as other posters and what I read here was remarkably reassuring, as a glitchy electrical outlet is far preferable to some crippling, expensive hardware failure — especially to a troubleshooting luddite such as myself. However…

I’ve plugged the machine into a different outlet, thinking that would solve my problem as the one it was in when the bizarre behavior began was a little crowded. No dice. So I tried another, and another, in different rooms all over the house. Still having the same problems. I’ve run Hardware Test and checked the diagnostic LEDs inside, and everything checks out. I followed the suggestions of some of the posters here, such as resetting the SMU and deleting the plist files but nothing has helped.

The one thing I haven’t done — the first thing you suggest, as a matter of fact — is plugging my iMac into a UPS, mostly because I don’t have one handy and hoped that if the machine worked in another outlet I could buy one with the confidence that it’d be solving my problem. Obviously, from my past week of research I’ve learned that it’s not a bad idea to have a UPS anyway, but my concern for now is fixing this maddening little box.

My question is, should I still buy a UPS and try that, or just resign myself that this is an internal rather than external issue, say, maybe a failing power supply or something along those lines?

I should also say that I bought this machine used (it was originally purchased in Sept. 05) so I don’t think I am covered by Apple’s warranty, correct?

Thanks in advance for any light you can shed on my situation and thanks also for all the knowledge you’ve dropped already.

Hi Justin - thanks for adding your experience to the blog. When you do finally nail down this problem and get it solved, it would be great if you could add a comment letting us know what finally did the trick for you.

From what I've seen and heard in the blog and in email, it looks like this particular error is caused by anything that results in the power being interrupted to the mother board. This can range from the simple (a bad cord, a power failure, power quality problems, a bad UPS) to the major (bad power supply, bad power management hardware, even a main logic board failure). Apple support is notoriously ill-informed about this error, and the scripts they walk you through vary from user to user.

I've found that the best way is to start with the simple and cheap: as you already have, try a different outlet (you may have a bad outlet or circuit in your home); try a different power cord; try to borrow a friends UPS overnight or something. Of course, I'm a huge believer in UPS's no matter what, so I never think it's a lost cause to purchase one :-) Note that a decent but small UPS (it's good for just transient power failures) can be had for under $40, such as the APC ES 350 or BE 325. After that, if the problem remains, you need to dig into the hardware - which may mean working with your local Apple dealer or Apple Store "genius bar" people. I've heard of the power supply being the culprit, and also the main logic board. Neither is cheap or easy, and I haven't heard of any reliable way to nail down the exact culprit.

I hope that your problem still manages to fall into the cheap-and-easy category (don't forget to check that power cord and [if applicable] external power supply!). Good luck!

  ..Chris..

I ran into this problem twice today for the first time in several years of owning this G5.

My current theory is that it's an overheating problem, since it occurred during particular heavy usage of the OpenGL card. I have played WoW on this card extensively and never had the problem. However, today, I was in an area that was incredibly highly populated and no doubt driving the graphics card to its limits.

I'm going to observe it and will report back any more findings.

Wade

I've been having the same problem since yesterday morning. When I check the system log its the same -122 error code.

Daniel - that's very interesting, this is the first time I've heard any mention of the internal Airport card in relation to the -122 error.

The only direct experience I've had was with my G5 Tower, which definitely did not have an Airport card in it at all. In that specific case, the eventual culprit turned out to be an external UPS that was failing due to a bad battery cartridge.

I'll definitely be very interested to hear how your experience turns out; if the Airport card is involved, it's a whole new troubleshooting area to try out!

Thanks for posting,

  ..Chris..

Update: Problem solved.

I had the problem again yesterday. The machine shut down twice. On the third time, it would not even reboot. I'd press the power button and it would just click. The little light would come on and go off immediately.

Eventually I figured out the problem was a bad firewire cable I had connected to the front firewire port. The other end was not connected. When I pulled that cable out, the machine would start and run normally. As soon as I plugged it back in (including in the rear port), the machine would shut down. Interestingly, that cable had worked fine for years.

So, the cable is in the trash and the machine is operating well again.

Wade

Hi Wade - that's great news that you solved your problem, and even better you've added a whole new (CHEAP) thing to check and troubleshoot before you get plunged into the motherboard replacement game!

Thanks very much for the update; I'm going to go add this to the "Troubleshooting" section of the updated article elsewhere in this blog right now.

Cheers!

  ..Chris..

Hi guys, I've been experiencing the same issue for a few weeks. Going to try some of the suggested fixes to see if anything works. I've put up my system profile here:
http://www.falzon.biz/imac/Andy's%20imac.rtf
In the hope that maybe it will help find a common component.

imac:/var/log mcduff$ cat system.log |grep shut
Feb 10 20:46:12 localhost kernel[0]: AppleSMU -- shutdown cause = -122
Feb 11 06:11:12 imac shutdown: reboot by mcduff:
Feb 11 06:12:09 localhost kernel[0]: AppleSMU -- shutdown cause = 2
Feb 11 16:46:00 localhost kernel[0]: AppleSMU -- shutdown cause = -122
Feb 12 07:24:35 localhost kernel[0]: AppleSMU -- shutdown cause = -122
Feb 12 07:40:18 localhost kernel[0]: AppleSMU -- shutdown cause = -122

Andy - for a good collection of troubleshooting tips in one place, check out the Troubleshooting section of a new article in this blog covering the -122 problem. Here's a quick link to it if you'd like.

Good luck, and let us know how it comes out for you.

..Chris..

Hi, just found out this page while googling why my Pismo was shutting down while sleeping. In my case it's a "ApplePMU::PMU forced shutdown, cause = -96". Of course, I'd really like to know what this means...

I don't have any specific info on the -96 error, but it seems to be reported mostly on portables. You might want to go through some of the standard debugging first steps (resetting the PMU, tossing your preferences files, etc.). I'd also look to see if it happens when you're only on batteries, only on A/C power, or both. But in the end, it might well mean a call to Apple, who are the only ones who have the official list of the PMU error codes.

  ..Chris..

P.S. for a convenient list of some of what I described here, check out the Troubleshooting section of the updated and revised article about the -122 error in this blog, here.

Just to follow up on my intermittent shutdown issues. 3 weeks ago my 20" Imac shut down and this time wouldn't restart. I took it to my nearest apple store (still under warranty) and they imediately diagnosed it as a power supply. I told them that for the last month or so it had been shutting down randomly.. to that they just nodded.. yep, definately power supply. After a 16 day wait for the part (warehouse was empty here in Aus) I now have my Imac back and it appears stable.

Thanks
Andy