Sony VAIO PCGNV200 Series User Manual page 130

To adjust the volume using the volume dial control

Rotate the volume dial control clockwise to increase the volume.
 Rotate the volume dial control counterclockwise to decrease the volume.
When you use the Volume icon
Volume icon, the volume dial control adjusts only the sound level from the speakers or headphones.
The volume dial control will work only when the Volume icon
to increase the volume you also increase the volume dial control volume. Unlike the
is set to an audible level.
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