Narcoleptic iMac 20" PPC G5 Sleeps while in use.

iMac 20" PPC G5 2.1GHz OS 10.4.10 (purchased new November 2005)

Recently I've begun to experience my iMac going to sleep after using it for awhile. While actively using the computer, the cursor disappears, the screen dims then goes blank. If I hit the cursor bar, it comes back to life without losing my place in Safari, or whatever other application is active.

This condition may have started about a week ago. When the computer has been off for a while, I seem to be able to work until the back of the display heats up pretty good. My conclusion - based on gut feeling nothing more.

My energy saver control panel is set to put computer to sleep when it is inactive for 1 hour. I set that the first day and haven't changed that setting. The display sleep setting is set to sleep display if inactive for 15 min. That also hasn't been changed.

(Also the DVD drive started throwing off error messages about 6 months ago. I stopped using it as the burned discs were unreliable.)

I'm not concerned with the DVD burner, but the going to sleep is becoming more and more disconcerting.

Welcome to Mac-Forums, gernikako. Soory to hear about your iMac G5 problems. Are still under warranty with extended AppleCare? Seems that they should be made aware of this.

What I find perplexing is that it seems to be exhibiting power supply issues but your model would be excluded from the recall. Might be a good idea to check your serial number with those listed here just in case.

And for safe measure, check these out too.

Narcoleptic iMac EMC: 2082

Unfortunately, my EMC doesn't correspond to the repair cited. It is not under warranty as I didn't get the extended care.

SOL?

You could always run Apple's Hardware Test (because I for one am pretty sure this is a hardware problem - like I said, this sounds suspiciously like the power supply problem the earlier iMac G5 generations experienced) but if the problem is intermittent, there is a good chance it won't see it. But running it anyway wouldn't hurt either. Just insert the DVD in the optical drive and restart holding down the C key. When prompted, select the Hardware Test and ask for the extended test. It will take a while: at the end you will get a report and if the test found anything, it will be listed there.

SOL? It depends on how much you value your Mac: if you want to keep it, you could always take it to a Mac shop and get an estimate of the costs.

On my iMac G5 the hardware test is on the restore DVD. To get to it I have to hold down OPTION instead of C.

Option? Oopsie!

Thanks for the heads up, dtravis.

Do you have a hot corner set up to sleep, and perhaps your cursor is going into the corner?

When I upended my computer to look for the EMC code, I noticed that the round vent hole above the power cord was PLUGGED with fine dark grey dust!!! I sensed that the computer was heating up rapidly and thought that might have something to do with the sleep condition.

Lo-tech solution: I took out the vacuum cleaner, sucked all the dust out of every nook and cranny. The computer hasn't unexpectedly gone to sleep since!!! It's been 4 days. I think it's cured it of its narcoleptic fits.

Thanks for all your input, nonetheless. Hopefully this is the end of this thread.