[X4U] odd iMac G5 fan behavior upon waking up.

[John Richardson]

Hello,

I had the energy saver settings enabled and set to put the computer to sleep
after 15 minutes of inactivity and also to put the hard disks to sleep
whenever possible.

Under normal circumstances  I would move the mouse and hit the enter key.
Then after a few seconds I would get the screen saver password. However,
twice recently and I believe once or twice over the last 3 months the
following happened.

1) I attempted to wake up the computer by moving the mouse and clicking the
mouse button and then by hitting the enter keys.

2) The power indicator light went off and the screen remained dark. After
about 30 seconds or so, the fan came on. The fan ran at a very high rate and
made a significant amount of noise. This continued for over a minute. I
pushed the power button. Nothing happened. This went on for some time and I
did not have immediate access to my OS X manuals. So I shut off the power
strip. One of the times this happened I held down the power button in the
back for 5-10 seconds and the system seemed to respond with a screen full of
happy Mac desktop icons.....

The computer seems to be OK. I immediately disabled the energy saver
settings.

What happened? Why? Also, what is the recovery procedure for future
reference?

John F. Richardson