I've got a PowerBook G4 15" 1.0 Ghz Aluminum that's almost 3 years old. On occasion, the powerbrick just stops working. I'll wonder why my screen has dimmed a bit, look over, and the charge light will be off. Dissconnecting the adaptor at the wall and plugging it back in fixes the issue. This has happened half a dozen times or so in the past couple of days. It's not a problem with my powerstrip, as it has also happened when plugged directly into the wall. It has also occured with both the extension cord connected and disconnected. I'm fairly certain it has not gone through a power surge. If it keeps it up, I'll call AppleCare, since I still have a couple months left in the warranty. Any ideas as to why this is occurring? Thank you.