Mac OS X: iMac G5 spontaneous restart
iMac G5 spontaneous restart
by DiligentlyDoubtful - 2/15/06 5:21 PMI have an iMac G5 20-inch, 2.0 GHZ, 1.5 GB RAM - last night I left my Mac on as I usually do and in the morning I noticed the Mac was off. I figured something happened with the power during the night and it just shut off to protect itself. Anyhow I hit the button and it looked like it was starting up normally but after a little bit, before the log in screen, it shut off again. I tried again with the same result. I had to leave so I unplugged and when I came back I tried again...which was about 4 hours and it still wasn't staying on but it got a little closer to the log in screen than before. I had to leave again and when I came back it started up...however spontaniously during use it has shut off. Right now I am using it to type this message and this is the longest it has stayed on all day.
I'm unsure of what I can check and I haven't found many resources on this problem online. Most of the information that is close says that there should be an error message at the next start up, but I do not recieve one. If anyone has any suggestions it would be greatly appreciated.
First things first
by mrmacfixit
- 2/15/06 6:41 PM
In reply to: iMac G5 spontaneous restart by DiligentlyDoubtful
Can you start the machine up from the OS X disk that came with it or from another OS X installation disk?
If Yes, then the system is corrupt and an Archive and Install should fix it.
If No, and the problem is the same, it's time to sit down and think about the problem. Any new hardware additions, internal or external, lately?
P
re: First things first
by DiligentlyDoubtful - 2/15/06 9:09 PM In reply to: First things first by mrmacfixit
Nothing newly added to the computer. As well it starts up now but on occasion it'll shut off without warning.
I'm fairly confident the OS is all right because it seems to start up ok and work normally up until the point that the problem of it shutting off happens (obviously).
Could it be a problem with the power supply? I wouldn't know how to test if it were but I need this computer up and running and reliable as I do some design intensive work which requires the Mac.
Thanks for your help.
First Things First
by printit - 2/24/06 3:57 AM In reply to: re: First things first by DiligentlyDoubtfulCheck out the power supply! I had the same problem with my PC; it would reboot every time I attempted to use a drive.
Power Supply
by mrmacfixit - 2/24/06 4:52 AM
In reply to: re: First things first by DiligentlyDoubtful
I tend to agree with your diagnosis.
Is the machine covered by AppleCare by any chance?
If so, get Apple to fix it for free
P
IMac 20in 1.8ghz 2g memory, OS 10.3.9. Forced restarts
by no comprehendo - 3/16/06 9:49 PM In reply to: First things first by mrmacfixit
Every once in a while, a shadowy overlay appears on the screen that informs me, in about five languages (sic) that I have to reboot the computer. Whatever I'm working on, unless I have already saved it, is lost.
Kernel Panic
by mrmacfixit - 3/17/06 4:54 AM
In reply to: IMac 20in 1.8ghz 2g memory, OS 10.3.9. Forced restarts by no comprehendo
If your memory was purchased from a third party, remove it and see if the problem still happens.
Faulty RAM will cause this symptom
P
Another thing to check
by SantiagoCrespo - 2/24/06 4:52 AM
In reply to: iMac G5 spontaneous restart by DiligentlyDoubtful
After having almost killed a computer or two in my lifetime, I would suggest you check if all the internal cooling fans are working on the thing.
Many computers have thermal protection sensors which will turn the computer off if the temperature goes above a specified threshold (usually 96 Celsius). A stuck or "almost" stuck cooling fan could be the culprit.
Saludos.
Power Problems
by mrmacfixit - 2/24/06 6:11 AM
In reply to: iMac G5 spontaneous restart by DiligentlyDoubtful
As mentioned, it could be a thermal problem but if it was you should be hearing all the fans running at high power for a short period.
The SMU is controlled by the OS and if the SMU receives no input from the OS for 2 minutes, it runs all the internal fans at high speed. You will hear this freight train in the next room!
Try this to reset the System Management Unit, SMU, which controls a bunch of stuff including the climate inside the iMac
Resetting the SMU (System Management Unit)
1. Unplug all cables from the computer, including the power cord.
2. Wait 10 seconds.
3. Plug in the power cord while simultaneously pressing and holding the power button on
the back of the computer.
4. Let go of the power button.
5. Press the power button once more to start up your iMac G5.
If it fixes the problem, great. If not, it will not have done any harm.
Now, given that the SMU is contolled by the OS, there could be a possibility, however slight, that the OS is not doing its job correctly. In this case, it could well be that an Archive and Install is the answer.
P
RAM and logic board
by mwaldyke - 2/24/06 7:23 PM In reply to: iMac G5 spontaneous restart by DiligentlyDoubtfulI had a similar problem on a G4 Power Mac some years ago. In that case two of the RAM slots had become unreliable. As long as RAM was present in those slots, RAM errors occurred frequently enough that the system would become unstable and cause the computer to reboot itself. In my case it turned out to be a logic board problem (ouch), but bad memory also occurs occasionally.
Since I would guess this is pretty rare, try the other ideas first (they're all good thoughts). But keep this in mind if none of them pan out. And I also echo that if it is still covered under warrantee or Apple Care, get it in for free service.
IMac restart
by scottae316 - 2/24/06 8:51 PM In reply to: iMac G5 spontaneous restart by DiligentlyDoubtfulGet your serial number from the bottom of your iMac and the go to the Apple web site under support. Look for the warrant extension section for the G5 iMac's. If your iMac serial number is in this range for 1st generaton iMacs, you probably have a faulty power supply and it may have caused damage to the logic board. If you have an Apple Store near by, call and take it in. If you deal with an authorized reseller, check to see if they are an authorized repair center for Apple. Mant CompUsa's are also authorized to repair Apples. If none of these avaiable, call Apple. Hope this helps.
Scott
Good Call!
by mrmacfixit - 2/25/06 6:31 AM
In reply to: IMac restart by scottae316
I missed that one
P
spontaneous restart
by TCALLDAY - 2/27/06 4:23 PM In reply to: iMac G5 spontaneous restart by DiligentlyDoubtfulIv'e seen very similar problem's several times in PC's. It's been the powers supplies in all of these cases. Use the power voltage monitor for the power suply or download and install one if your OS doesn't have one. Watch the voltages and see what they tell you each case has been related to a storm in my area
a powersurge being the likly culprit
| Forum legend: | |
 |
Locked thread |
 |
Moderator |
 |
CNET staff |
 |
Samsung staff |
 |
Norton Authorized Support team |
 |
AVG staff |
 |
Windows Outreach team |
 |
Dell staff |
 |
Intel staff |
