Adjust mixer volumes
From MEPIS Documentation Wiki
Open KMix by clicking KMenu --> Multimedia --> KMix, or by clicking the speaker icon in the right end of the tray and clicking on "Mixer."
On the Output tab, make sure the Master volume (on the far left) is turned up. Also, make sure PCM is turned up (the control with the blue squiggly line above it). Make sure that the little round buttons (green lights) above these slider controls are on (lighted). On the Input tab, check that the channels you need (CD, etc.) are not muted. The mute buttons look like green LEDs.