Welcome to LQ.
Try the other plugs on the board and see what happens, just to be thorough.
Open the Pulse Audio Mixer (pavucontrol--if it's not already installed, it's in the Mint repos) and check the settings; adjust them as needed.
Also run alsactl from the command line and check the ALSA audio settings.
After that, start a new thread in the appropriate forum (Distributions-->Mint would be my suggestion) with your actions and their results, as this forum is just for introductions and actual Linux Questions in this forum may not get the exposure that deserve.
Last edited by frankbell; 11-02-2014 at 09:51 PM.