Keep playing with the headphone port using a jack. Or better yet, reconnect powered speakers just like the one on your desktop. If you hear both R & L speakers working, it's obvious your output amp still works. What most likely happened is that the port connector is not closing back (when you plug in a jack a contact in the port opens up to disable the built in speakers, and closes back when uplugged to reconnect the built in spkrs), try playing with it by plugging in the jack, turning it around and pulling it quick. Do this a couple of times and see if it will fix the problem. But if you do not hear the R & L speakers after connecting powered speakers, then most likely the amp went bad.