Yamaha O2R Owner's Manual page 307

• Solo Safe—Tape, Mic, Line, and Effects—These functions disable solo
On/Off selection. If you set a channel to Solo Safe while it was set to
Solo ON, the channel remains unconditionally ON in "Mixdown
Mode" when you select Solo.
This function has no effect in "Recording Mode".
How to use Solo
1. Press the [SOLO] button.
The LEDs inset in all the [ON] buttons start flashing.
2. Press the [ON] buttons for the channels you want to solo.
The LED inset in the [ON] button you select is illuminated steadily. If you
selected "Last Solo" in the Status command, only the last channel you
select will be soloed.
3. Press the [SOLO] button again to cancel the solo function.
Digital I/O, Setup, and Utilities 197
02R User's Guide