1995 Buick Riviera Owner's Manual - Page 135

Playing the Radio PWR: To turn the radio on, press the PWR button. Upper Knob: The upper knob does the following: Controls the volume. The VOL knob increases or decreases the volume whenit is held slightly rotated against the spring load. Volume is graphically displayed. 0 Allows you to MUTEthe radio or the CD. Press to mute; press again to listen. During mute, only volume up will work. 3-12