[sbeney]

I have an iMac G5 running Leopard (with latest update). Everything seemed okay last night when I shut the computer down, but this morning after starting and logging in to my main account (managed) the computer shut itself down after a few minutes. After playing with it for a few minutes it appears that it will either shut down or restart after some time (random amount). I ran Disk Utility from the Leopard disk and it reported no errors. I then restarted in my main account and tried to Repair Permissions. It seemed to hang during this, but not crash - I was able to hit stop repair. I tried to run the Apple Hardware test from the discs that came with the computer, but the computer kept shutting down when trying to boot from this disc. I have a back up of my Hard Drive using Time Machine.
Anybody experience similar problems or have any suggestions?
Thanks,
Stephen

[iSeeXiMac]

It sounds like it is over heating. Well what I can help with to see if its just a weird bug, try a PRAM reset. At start up press and hold the apple key(known as Command Key), Option(alt key), P and R, wait for 3 start up sounds then release it. If the problem persists try a Open Firmware Reset All Command. At start up(again...) press and hold command option O F. Keep holding until you see a white screen with text. Type "reset-all" without quotes then press return and it will automatically restart. If no go still and you still have Apple Care then I would suggest having Apple take a look at it. Of course when you do take it in let them know the diagnostics you have don't already so they don't have to do that again. I had almost the same problem as you do but in Tiger. But my video was fried out and it was freezing not shutting down. It took 2 logic board replacements to get it fixed. Anywho, good luck to you! /forums/ubbthreads/images/graemlins/grin.gif

[dommer]

Hi, I've been having the same problem with my intel imac, it started with a white stripe across the screen, which I thought was a screen problem, but a few weeks went by and now it started to shut down on me, right after i turn it on. Now it wont turn on at all... the fans start but that's as far as it goes no starting sound at all...
Any ideas... anyone..???
Cheers
Dom

[iSeeXiMac]

Take it to apple and get it fixed if you still have your warranty.

[jjkev]

I have a new iMac mid 2007 that is doing something similar - starts up fans run , spinning disk then it shuts off. I am a AASP and there is no answer in the service manual. Here's what I have found and it seems to fix it. Replace the DC Power Supply/SATA/Inverter cable (it'll have to be done by an authorized tech - terrible design of the system and it requires complete dismantling as the cable runs behind everything - even the stand support) and then a reinstall of the OS fixed my issue. Just replacing the cable alone didn't completly repair it - I am guessing the OS went corrupt during one of the many shutdowns after trying to start it.

good luck.

[patricci]

I have the same problem and starting using UPS to be sure it is not external electrical.

Genius bar did an archive and install and it still did it. Then they replaced power supply 661-4433 and logic board 661-4437 and cable S1401ll/a.

It worked ok for 3 days then shut down again.

I had been putting it to sleep each night but now I am turning it off at night.

I was told the machine did some stuff at night but I have no clue what it does.

Almost 3 days since last unexpected shut down.

[RWHegwood]

My new imac does the same thing. Started about 2 weeks after I got it. At first it was rare and intermitant...now its hard to keep it on at all. When I press the on button I often hear the fans kick in...or drive...something spinny...it chimes, revs up a little then goes dead again.

However I have discovered if I apply slight downward pressure to the left hand corner of the screen it will boot. It will also boot up if I squeeze the button corner a little as i press the button. But...once I let go it can be seconds, minutes or hours before it shuts off again on its own.

[Alan]

[~54156]

I tried the command/option O F and did not get that reaction. How come?

BTW I do not have the problem that was posted on this thread although I have a problem in that I have to hit the start button twice or hold it in about 4 to 5 seconds minimum to get it to start. Been like that for a very long time. Applecare said to bring it to a shop and I have been too lazy as this is not seeming to be affecting anything else.

[patricci]

My Imac shut itself off again after 2 weeks so I took it in again and Genius bar said erase and install so I took it home and spent time backing up my programs. They said not to use Time machine backup because it might have the problem in it's stuff.

I spent Thanksgiving day and following backing up, erasing, installing. I slowly put back my virtual machine VMware ad a couple of the PC programs. It shut down again but I had added the restart option after power outage and It did restart and I got a message from Microsoft saying the USB hub was a problem. It was v1 and so I bought a v2.

I did not have this problem when the Imac was at another location and I tried to remember what else was different. I did not have that hub at that location so I thought all was well but it happened again.

I guess I will just try documenting all I have running when it happens and hope there is a pattern.

I do have AVG running on the Virtual machine.

[Bethos]

I've been looking for info on this. My iMac (new in early 2008) started rebooting randomly two weeks ago. It started once every few hours, then more frequently and eventually would reboot every 2-3 mins. Brought to apple store, they replaced the power supply. It worked for one day, and now has started rebooting again. Taking to apple store tonight.

[mseabloom]

I'm currently in the midst of the same issue with my mid-2007 reburb 20" iMac. Power supply was replaced last month. Still shut down on me. I took it back in to the Apple store today and they are ordering a new logic board. Sounds like the standard routine they go through with the issue. Hopefully the logic board will take care of things, but from everything I'm reading about this problem, I have my doubts :-/

[patricci]

I am still having the problem but very less often. I am running Vmware Fusion virtual machine and that may be contributing to the problem. One time when it happened I received a message from Microsoft saying the problem may be a usb hub. So I got a new one and have eliminated my use of a hub and still it happens. InXP there is a setting to restart after power failure so I have that running and it starts up faster.

I am using the UPS so it is not electrical.

Really weird!!!

[rossenrode]

With over 25 years on Macs, I've always been an avid supporter (and user of course) of Apple products, but that 'support' is wearing thin these days, as over the last 6 or 7 years, I am seeing a 'pattern' with my Macs 'dying' on me after around three years - (and by strange coincidence, always after my extended warranty period!! Hmmm?). It happened to my 2003 iMac, my 2005 white iBook and it has just happened to my 2007 22" iMac. The first two were logic boards packing up...and after four replacements in all, I gave up. And now it would appear I have a logic board failure on my iMac..and I am really fed up, especially as I am a freelancer and just cannot afford this kind of major hassle and cost, on an almost 'regular' period!! I see mention of a number of other possible 'explanations' for my iMac 'starting' but not booting up, but just maybe it is a power problem... PS I am typing this on a month-old MacBook Pro and I now wonder what to expect in three years time with this one...

Maybe Apple should beging offering a 4 or 5 year extended warranty...or maybe simply say - "see you in three years", as you leave with your new purchase!!

PS: Interestingly, my original 'Bondi Blue' iMac I bought in 1998 is STILL working !! (not much use to me, but working none-the-less)

Ian

[jackbauer24]

have you ruled out bad/broken memory?

i've had this happen, although on my 1 year old dell vista machine. sorry, my mac pro is running great but i want to help. with me dell, the main reason for my dell rebooting by itself was a bad memory stick. went from 4 gb to 3gb, threw away the 1 bad stick, and everything runs great. since i switched last year anyway, that's just a email/browsing machine for the mrs.