Con Google se encuentra fácil el manual.
Dice:
"Once you have saved changes to a preset program, you can
still recall the original settings. To enter the RESTORE
FACTORY PRESETS mode, simp
ly hold down the VALUE
knob as you turn the unit on and then select the program to
be restored (or AL for all programs). Press the VALUE knob
to confirm your selection. Any program changes you have
made will be lost, so you might want to copy the program to
another location first"