GT-PRO: Initializing - Restoring the Factory Settings
The following procedure can be used to clear the internal memory and reload the factory settings:
(CAUTION: All USER information will be lost. Be sure to back up any information you wish to keep.)
1. Power on while simultaneously holding the PREAMP/SPEAKER ON/OFF button and the PREAMP/SPEAKER TYPE VARIATION button.
2. When "FACTORY RESET" shows in the display, release both buttons, and then press the WRITE button.