I've got a coworker who has a 15 month old PowerBook G4 12" 1GHz, no AppleCare. She plays iTunes on it using the internal speakers, and recently she's discovered that it will randomly switch to the audio port for output rather than the internal speakers. I observed this myself, just now. We turned on iTunes and set it playing and watch the Output tab in the Sound System Preferences. There was nothing plugged into the audio port, but after a while it switched back and forth between "internal speakers" and "headphones" in the preferences. I plugged in headphones and the audio output was normal. It did not switch to internal speakers when the headphones were plugged in. After I unplugged them it switched back and forth a bit more and stayed on headphones. There is nothing visibly obstructing the port. Nothing in it. I'm wondering if perhaps the audio jack is bad, or perhaps something else on the motherboard is. I've googled and googled and can't seem to find any prior occurrance of this problem. I'll have her take it to the Apple Store and have the "Genius" look at it. I'm hoping she doesn't have to get the mobo replaced. I'd appreciate it if anyone has insight into what may be causing this. Moral of the story: always buy AppleCare for laptops.