Panasonic Toughbook CF-C1ADAAZ6M Reference Manual page 188

Troubleshooting (Advanced)
Problems with Sound
The sound is not heard
Try changing the mute by pressing Fn + F4 or Fn + F5 / Fn + F6.
With the following procedure, check that the Windows sound function is operating.
(If it is not operating, pressing Fn + F5 or Fn + F6 displays the pop-up icon shown on the right, but there is no sound.)
Windows 7
A
Click (Start) - [Computer] - [System properties] - [Device Manager].
Windows XP
Click [Start] - [Control Panel] - [Performance and Maintenance] - [System] - [Hardware] - [Device Manager].
Double-click [Sound, video and game controllers] and check if
B
If or is displayed, click the driver for which
deletion screen. Then restart the computer.
To change the volume
Press Fn + F5 (to lower the volume) or Fn + F6 (to increase the volume).
<CF-C1 Series>
A clacking sound is heard while operating the screen with the pen (included)
The built-in microphone is picking up the pen operation sounds.
Mute the microphone.
The audio is distorted
During audio playback, operating a key with Fn may cause distortion of the sound. Stop playing and start again.
or is displayed.
is shown, press Del, and click [OK] in the confirm
or
188