As of GT-1000CORE System Program Ver.2, the AUTO OFF function has been updated to comply with the ErP Directive. The power now automatically turns off after 20 minutes of inactivity.
To change the AUTO OFF setting, choose [MENU] → "HARDWARE SETTING" → "OTHER" and turn knob [1] to select a value (20MIN, 1HOUR, 5HOURS, 10HOURS, or OFF).