IMac shuts down intermittently.

Mine is doing the same thing. Seems to only happen when I am playing music from Itunes library in the background while working. After about an hour it shuts down. I have tried looking at Energy Saver, etc. It definitely is not a heat issue. I am stumped!!!!!

I juts received and set the machine up today. love it....when it stays on.

This is a huge issue and there are several topics on this. Yes it's no rhyme or reason. Just like power cut off at the wall. I had a few dozen posts on this but somehow I had to resign up so it looks as if I have posted only a few times. as yet, I don't know if they know why.

To all,
Mrtotes has a good point here. Download and run something like Temperature Monitor:
http://www.bresink.de/osx/TemperatureMonitor.html

That would be one of the first things to consider if a computer runs normally and suddenly shuts down. There was just a case here where the lower housing screws were loose. Here's the appropriate quote from the service manual:
"Replacement Note:
These torx screws must be tightened to at least 17 in.-lbs. If you do
not have a torque driver, you will have to make sure these screws are tightened by hand FIRMLY, BUT NOT FORCIBLY. Or, purchase the service tool (076-0899) in order to ensure the thermal pipe is firmly mated with the top base. If the bottom housing is not securely attached to the base in this fashion, the CPU may overheat and become damaged. For
more information, refer to “Thermal Paste Application’” in this chapter."
"Thermal Paste Application
Tools
This procedure requires the following tools:
• Plastic stylus or plastic spatula to remove the old thermal paste
• Plastic stylus or plastic spatula to spread the thermal paste
• Thermal paste (922-4757)

Thermal Paste Application
Procedure
1. Thoroughly clean the original thermal film from the mating surfaces (circled below) of the bottom housing and thermal pipe. Use a plastic stylus to scrape the surfaces clean.
Note:
Do not use an abrasive material or liquid cleaner.
2. Squeeze a thin film of thermal paste onto the mating surfaces of the thermal pipe." (there's been references here to Arctic Silver from RS and a later version that's better)

This would always be something to look for if you suspect or know the computer has ever been apart. These iMacs are not easy to get together correctly and the heat pipe routing is a definite "Gottcha!".
Richard

I feel your pain, well, almost. My system shuts down for no reason as well, it started about 30 minutes after I got it out of the box and got worse over time (1 a couple of weeks to every 5 minutes after 4 months). My IMAC is right at 1 year old, I purchased it at Frys. I get a loner if my IMAC is being worked on. So for the last year Fry's and Apple have had my system more than me. I am on my 3rd loner from Frys, I have gone back and forth with loner to my lemon 3 times. Each time they tell me to pick it up it will start shutting down after about an hour and wont stop. Just got done with a time machine restore to loner. Fry's sent it to Apple, they claim to have replaced the drive and logic board. Not sure what to think, all loners work fine.

Here are my specs, curious if yours is the same
Model Identifier: iMac7,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 3 GB
Bus Speed: 800 MHz
Boot ROM Version: IM71.007A.B03
SMC Version: 1.20f4

About two weeks ago my G4 flat panel started crashing intermittently. Half the time it just would not start up again until it had been left for a while. Thinking the hard drive was overloaded, I backed up all my files and did a clean install of Tiger. (It now has 27 Gigs available.) It was fine for a few days, then it crashed again yesterday! I reset PRAM and NVRAM. I switched off the sleep option, thinking it might be causing the crashes. Then, this morning it crashed again!!! 😟 This time I was able to copy this information:
panic (cpu 0 caller 0xFFF0003): 0x300 - Data access
Latest stack backtrace for cpu 0:
Backtrace:
0x000954F8 0x00095A10 0x00026898 0x000ABB80
Proceeding back via exception chain:
Exception state (sv=0x29E70000)
PC=0x000A5440; MSR=0x00001030; DAR=0x00000037; DSISR=0x42000000; LR=0x000A7F48; R1=0x0036DB20; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x000A7F48 0x000ABB80
Exception state (sv=0x29E27780)
PC=0x00017874; MSR=0x00021030; DAR=0xDFEDC4E0; DSISR=0x40000000; LR=0x00017FFC; R1=0x0036DCD0; XCP=0x0000001C (0x700 - Program)
Backtrace:
0x00017BE0 0x00017FFC 0x00018370 0x000C5850 0x00096090 0x00095CAC
0x000AC6EC
Exception state (sv=0x33271780)
PC=0x0027AFE8; MSR=0x00009030; DAR=0x000001D1; DSISR=0x42000000; LR=0x005FB43C; R1=0x000001E1; XCP=0x0000000c (0x300 - Data access)
Backtrace:

backtrace terminated - unaligned frame address: 0x000001E1

Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.IONetworkingFamily(1.5.0)@0x5ec000
Exception state 9sv=0x223CE780)
PC=ox00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=oxoooooooo; XCP=0x00000000 (Unknown)

Kernel version:
Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
panic: We are hanging here...

From the little I know this looks like a kernel panic. Does anyone know for sure and can you tell from the information what caused the panic?

I haven't yet checked the RAM chip (XDEALRAM 512 MB for flat panel iMac G4 PC133 SO DIMM) I bought from 18004MEMORY and installed in April.

HELP!



700 MHz PowerPC G4 / 768 SDRAM