Factory Reset / Initialize Sound

1. Press and hold the Shift key (k).
2. Briefly press the Utility key (f).
3. Release the Shift key.
4. Turn the Page Dial (c) clockwise until the display shows Init Sound.
5. Briefly press the Utility key (f) while holding the Shift key again to confirm.

Source: Microwave II — wdf007.raw (manual)