Hi Craig,

You can perform a factory reset on the amp, details below

To perform a factory reset:
• Power OFF the amplifier using the ON/OFF switch (#13 in this manual).
• Whilst holding down the AMP Section Switch, turn the power ON.
• The screen will display a notification that the amplifier is about to be returned to its
factory settings.
• If you are sure that you want to perform a factory reset, press and hold the EXIT/STORE
switch to confirm.
• If you do not want to restore the factory presets, pressing any other switch will cancel
the
factory reset operation and boot the amplifier as normal

Kind regards

Marshall Support