iMac G5: overheating problems?

Om Malik mentions some buzz about iMac G5 machines encountering overheating problems, resulting in power supply brownouts and fan problems. One iMac G5 owner reports the power supply completely flamed out, actually leaving scorch marks on the motherboard. Because the machine was designed to be almost completely user-serviceable, he was able to order and swap out the replacement parts himself, but delivery of said parts was delayed for a few days because of 'stock issues' — indicating this may not be an isolated occurrence. It does seem that cramming a G5 processor into such a tight space would lend itself to overheating, so iMac G5 owners might be wise to make sure their machines get put to sleep when not in use. Apple has posted a document that describes four LED indicator lights nestled behind the back cover of the machine, one of which should indicate whether or not the computer is overheating — be prepared!