The difficulties everyone describes seem to be one of 2 separate problems.
Every once in a while, for some unknown reason, the audio amp will cut out on one side or the other. I've discovered that cranking the volume to full usually fixes this particular problem within about 10-15 seconds.
If that doesn't do the deed, then the headphone jack is loose. If you've got any electronics or soldering background, check out the sticky at the top of the forum. If you can disassemble the unit down to
this point, you can look at the underside of the audio board. One of the pins on the headphone jack needs to be re-soldered, but do ALL of them just to be sure.