Apple have made an interesting headphone port for the MacBook (and some other Intel Mac models). It works like a standard jack:
- nothing plugged in -> audio comes out of built-in speakers
- headphones/external speakers plugged in -> plays through headphones/external speakers
but you can also use a special adapter (which trips a tiny microswitch) to get an optical audio out signal (which you can presumably plug into a nice surround-sound system).
This is all well and good except when, like auto-tracking, it doesn't work, and you are left with nothing to adjust. Users report that they get no sound when they have nothing plugged in and that a red light emanates from the headphone port. If you go to System Preferences -> Sound -> Output, it will say (IIRC) "Optical Out" instead of "Internal Speakers".
The only solution I'm aware of is to try to reset the switch by inserting and removing a set of headphones or a toothpick, perhaps wiggling it inside of the port, and hoping that you luck out and get it.
Are there other ways to fix this problem? Does anyone know where the microswitch is or have a good technique to reset it?