Sony SRW-5100 Operation Manual page 86

To return to the default settings
Press the cursor center button. The cursor item returns to
the default.
To revert the source tracks of all channels to
default settings
Press the [F9] (SDOUT ALL RESET) button in the
ALT+SD OUT menu.
The source tracks of all channels return to their default
settings.
You can also make the source track selection using the
VTR SETUP menu item 836 "SD AUDIO OUTPUT
EXCHANGE".
86
4-6 AUDIO Menu