IMac fans in shutdown

Hi - this is my first post on here - so please be gentle..!
I have just received my brand new iMac G5 20" iSight and I have to say it is an amazing machine.
I have, however, encountered a problem regarding the fans - one which, despite my search on this and other 'fan' related forum posts, seems to be quite unique.
I was burning my CD's to iTunes last night, for about 3hrs(!) I shut the iMac down (I needed to move it to another room) Next thing I know the fans come on and it sounds like it is going to take off.
I thought maybe it just needs to cool down and went to bed. Next thing I know I woke up at 5am this morning and the fans were still going, so I forced shutdown.
Anyone else experienced this or similar problem? Can anyone help??


Welcome to Apple Discussions.
People with the previous generations (iMac G5 Rev A, iMac Rev B/ALS) have noted this problem. Not good to hear it happening still in the iMac iSight. The IBM G5 processor runs very hot which is why fans have been a continuous issue in these tightly packed, stylish things of beauty.
I have this "take-off" fan on shutdown or restart 'glitch', and a search of these discussions will turn up others with the problem too. USB peripherals have been put forward as a one culprit.
Power down straight away if it happens again as with the OS shutdown and unable to monitor CPU temperature, the fans go into failsafe mode.
Log the occurance with Apple technical support/Apple Care, ASAP!