Computer shutting down

[Camille]

Hey.
Look, my iMac G5 is set, in the preferences, to start the screen saver when it's inactive for 10 minutes, and to put the display and the computer to sleep 5 minutes after the screen saver starts.
So, in the last 2 weeks, I noticed that after the screen saver is active for 5 minutes, instead of going to sleep like I set it, my mac just SHUTS DOWN!
So my iMac shuts down at least 5 times a day!!!
What's wrong??
A beg you, please help me!🙁
Thank you very much if you took the time to read my thread and try to help me...🙂

 

[CoMpX]

That certainly is a strange problem. The first thing I would do is reset the PMU, PRAM, and NVRAM. If this doesn't work then you could try to verify/repair permissions in Disk Utility. If none of this works then I would call Apple.

 

[Camille]

What does reseting PMU, PRAM, and NVRAM mean?
Does it reset preferences?

 

[Applespider]

Camille, you should really keep your 'old' thread active or at least refer to it in your new thread.

It will help anyone who can help diagnose since they can see what's already been suggested, tried and give more details of the problem

The link that CoMpX gave tells you what to do and what basically it's doing. But no, it won't wipe your application preferences.

 

[Camille]

So what will it do then?

 

[mad jew]

The linked article doesn't include how to reset the iMac SMU (which is the equivalent of the PMU on other Macs) but rather outlines how to reset the PRAM, the contents of which are listed at the bottom.

Status of AppleTalk
Serial Port Configuration and Port definition
Alarm clock setting
Application font
Serial printer location
Autokey rate
Autokey delay
Speaker volume
Attention (beep) sound
Double-click time
Caret blink time (insertion point rate)
Mouse scaling (mouse speed)
Startup disk
Menu blink count
Monitor depth
32-bit addressing
Virtual memory
RAM disk
Disk cache

All of these will be reset to the defaults. 🙂

 

[MacFan782040]

You may have gotten the iMac G5 Power bug! LOTS of people have this problem, including me.

The power supply in Rev A and B machines have something wrong with them (gets too hot or something) and shuts down.

Look on Apple's own discussion page, they have many posts on it.

I called Apple about it a week ago, they are actually having a technician sent here to replace it, then they want me to send the old power supply back to Apple and I'll be talking to them directly about it.

So basically, they recognize there's a problem and need more info to issue a recall.

 

[Camille]

Thank you!
But, what do I exactly need to do?

 

[mad jew]

Erm, are you allergic to hyperlinks? That sucks. 😀

Shut down the computer.
Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.

 

[Camille]

But It Doesn't Help!