Try this link to see if your power supply is faulty : http://docs.info.apple.com/article.html?... I have the same computer and my second power supply died in it this week. After opening up the power supplies I found some cracked resistors (actually the same in both power supplies). I'm waiting for parts right now... I'll keep you posted when I'm done replacing them. I might as well write a guide to help other in that situation. Since this computer has gone vintage, it's quite hard to find a power supply for it... You may want to try eBay or classified adds.