[X4U] G5 Fan Run Amok

[Stephen Lanza]

I have a dual G5 2.0 that has been experiencing an unusual fan problem. On
random occasions where I haven't used the machine for a while (like
overnight), I come back to the machine to find the fan running continuously
at a high speed.

The system looks like it is asleep with the display turned off but if I try
to wake it up by pressing the mouse button or a key on the keyboard
absolutely nothing happens.

The only way to get out of it (so far) is to hold down the power button for
5 -1 0 seconds to power down the machine. A subsequent press of the power
button restarts the machine normally.

My questions are:

- Is this a known problem? I searched the Apple Knowledgebase but couldn't
find anything that matches the conditions except for references to resetting
the SMU to deal with fan problems.

- What is causing the fan to run wild?

- Is there a log file I can check to see if anything is wrong once the
system is restarted.

- Is it possible that the machine is being damaged by this condition? Should
I be worried that the machine will go belly up at some point?

Thanks for any help.

Stephen Lanza
Software Complement