I've mostly used the internal speakers on my 20" iMac 2ghz, although I have plugged in a cable to my surround sound system (standard mini->2rca, no optical) from time to time. I went to do so again recently and the sound is so insanely low that I have to turn my receiver to full blast to hear a peep! To make sure it wasn't a receiver problem, I tried using a pair of working headphones, and I can't hear anything. I checked the volume setting and made sure "Line out" was selected for output in System Prefs. I'm thinking this is a hardware issue, and just wanted to ask if theres anything else I could check before calling Apple?