Crashing iMac 24" - how to diagnose

[tenjin]

Hi,

I have an iMac 24" 3.06Ghz, about six months old.

I have started experiencing random but frequent complete system freezes.

This is what typically happens over a period of 5 minutes:

1. I get the odd app crash (often Thunderbird, but possibly only because that is always running; sometimes mail.app crashes, something Open Office etc. No pattern to it).

2. The fans start thrashing although iStat doesn't record a higher temperature than normal. That said, the top bar hangs early on in this process so I guess the temp could be spiking. The box does not feel overly hot though (for an iMac). Normal temp about 39 degrees C.

3. All app windows freeze, and I get the beach ball. Mouse still works

4. dock freezes. Mouse still works.

5. keyboard freezes. Only mouse working now.

6. have to power off

I also have a very annoying ghosting problem on the screen that has only just started happening.

I am a relatively recent switcher to Mac, and have a lot of experience administering / developing on Windows XP.

I'm happy to trawl through the logs, so could anyone give me any suggestions about what to look for, what could be wrong etc.

Thanks

D.

 

[Richard.John]

Speak to Apple.

 

[rdowns]

If you want to poke around, launch Console.app which you'll find in your Utilities folder.

 

[tenjin]

Hi,

Anything particular to look for, or any particular log to focus on?

I'm happy to use console.app, but there is a lot of text in there. As a relative newb on the Mac I'm not sure what is a normal message, and what would be indicative of an error.

If, for example, my problems are indicative of a HDD problem what should I look for, and in what log?

If bad memory is the culprit, where would I look specifically, and for what?

Thanks

D.

 

[AdeFowler]

For some quick tips have a look at:

http://www.macworld.com/article/44328/2005/04/tipstroubleshoot.html


Disconnect all peripheral except your keyboard and mouse obviously. Your Mac should have come with a Hardware Test Disk. Run that and see what it says.

 

[tenjin]

Hi,

Thanks for your messages.

I'm exploring the possibility that it is iTunes 8.0.1 as there is a lot of web traffic about iTunes causing problems very similar to mine when downloading podcasts.

I've been trying to pull down some large Mac Developer podcasts recently...

Cheers

D.

 

[ChrisA]

Hi,

Thanks for your messages.

I'm exploring the possibility that it is iTunes 8.0.1 as there is a lot of web traffic about iTunes causing problems very similar to mine when downloading podcasts.

This sounds like it's a hardware problem. If I had to bet, I'd guess and intermittent RAM failure. But I'm pretty sure it's hardware.

I think the reason yuo see it while downloading is only because downloads are a long running process. If a bit "flips" for in the kernel the machine would likley crash.