Over the past few weeks, I've noticed problems with my PowerBook's headphone jack. The headphone plugs don't stay seated in the jack, resulting in loss of audio in either one ear or both until I adjust the plug, at which point it will almost always happen again. I usually end up having to hold the plug in place to get consistent sound from both ears. At first, I thought it was just my headphones, so I borrowed a couple pairs from friends and ordered a backup pair from Amazon, all with the same results. I've peeked inside the jack once or twice and everything LOOKS fine...but what do I know? I'll be in downtown Chicago tomorrow and Thursday, so I plan on making a trip to the Apple Store, but is there anything else I should try beforehand? Thanks. Oh, and also: as I recall, the PB headphone jack is part of the logic board, correct?