Freeze during screen saver

Question

Gang,
I recently migrated from a G4/733 running OS 10.2.9 to a 1.9 iMac G5 running 10.3.4. This new machine sometimes freezes after the screen saver has been on for a few minutes. It's done it with the Cosmos and Nature Patterns sets. I don't think it has happened with the 2006 World Book set, but I haven't used that one for long.
I've had a handful of minor annoyances, but this one is worse because it causes me to have to shut the computer down using the power button.
I found this thread: http://discussions.apple.com/thread.jspa?messageID=742697&#742697
The first post implied that this was a noted problem on earlier G5s, but I haven't found earlier references to it, and that thread was locked so it isn't clear to me whether it's been resolved.
Any news on this problem? I stopped using screen savers a long time ago when CRTs got to a certain refresh rate, but I think they're recommended for these LCDs--not sure. I don't want to risk screen burn-in, especially since I do leave it running for stretchs of time playing music in iTunes.
Any advice appreciated!
_dennis

Answer 1

Hi, dennis.
I think the problem to which the archived (you noted locked) thread was referring is Power Mac G5 (Late 2004) 1.8GHz models stop responding randomly. That was specific to the Power Mac G5, not the iMac G5.
With LCDs, sleep or shutdown are preferred to screen savers for extended periods of inactivity. See "Screen Savers: Using With Liquid Crystal Displays." I'd recommend you set the Display Sleep to a short inactivity period, e.g. five minutes, in Energy Saver preferences vs. using the screen saver.
As to the specific problem you've noted, freezes and hangs often have causes similar to kernel panics: the basic troubleshooting and hardware testing steps would be the same. See my "Resolving Kernel Panics" FAQ.
As far as general iMac G5 troubleshooting goes:
1. The first thing I would suggest is ruling out potential hardware problems. Run the Apple Hardware Test that came with the computer. Instructions for doing so will be found in the hardcopy manual that accompanied your computer.
2. Check the diagnostic LEDs, a feature of your iMac G5. See "About the iMac G5 diagnostic LEDs."
3. If your iMac G5 will not turn on, see "iMac G5: Troubleshooting when your computer won't turn on."
4. See also the new iMac G5 Support site.
5. Check the iMac G5 Discussions for similar reports from other users.
6. As a general check, run the procedure specified in my "Resolving Disk, Permission, and Cache Corruption" FAQ. Perform the steps therein in the order specified. In your situation, I'd consider it a long shot, but it will determine if there are any issues with some "common troublemakers."
7. If the computer is either under warranty or covered by an AppleCare Protection Plan, don't hesitate to take advantage of your warranty and contact AppleCare.
Good luck!
Dr. Smoke
Author: Troubleshooting Mac® OS X
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I may receive some form of compensation, financial or otherwise, from my recommendation or link.