Troubleshooting Linux Sound Card Issues
Problems like having the sound card installed and appearing in the list of installed devices but not playing sound when enabled.
First ensure pulseaudio is installed and run:
sudo apt-get install alsa-utils alsamixer
Press F6 in the alsamixer to select sound card and select your sound card.
This does not enable that card but selects it to allow you to change its options.
Try changing the "Analog Output" option and see if the sound starts working - "Multichannel" fixed it for me.
If this solution does not work try installing and running pavucontrol and playing with those options.