Sound Output changes from Built-in to Digital
Every so often my sound output changes from the built-in audio to the optical digital-out port.
Dual 2 GHz PowerPC G5, Mac OS X (10.3.9)
I don't think there is a real fix to the problem, there was a thread about this a while back and no one came up with anything, but to just get it to go back to built-in output, try plugging an 1/8th inch cable into the audio out jack, then either a) jiggle the plug in the jack (seems to have worked for other people) or b) adjust the computer volume (worked for me - I used the keyboard buttons rather than the sound preferences to do it, not sure if it makes a difference), then unplug it, and your sound output SHOULD change back to your internal speakers. Hopefully. Try both methods a couple of times if it doesn't.