Yamaha DSP -A780 - Manual (Page 25)

3. Changing brightness of the display (DIMMER)
You can select one of the five levels of brightness of the display.
4. Locking DSP parameters and other adjustments
(MEMORY GUARD)
If you wish to prevent accidental alteration to DSP parameters or
other adjustments on this unit, select “ON”. In this position, they are
locked and cannot be changed. The following functions on this unit
can be locked by this operation.
• DSP parameters
• Other setting/adjustment items in the “SET MENU” mode
(INPUT TRIM/CENTER MODE/DIMMER)
• INPUT TRIM control
• TEST switch
23