Black Keys Volume Control
If the volume of the black keys is different than the white keys, they can be adjusted to match.
Black Key Volume instructions
Piano keys 2 and 10 + Power ON - Press and hold keys 2 and
10 while turning the power on. A chime will sound confirming that
you are in the setup mode.
Piano keys 2 and 10 - Continue holding the two keys.
Piano key 16, 18, … 32 or 33 - Select the volume level that best
matches the white key volume. (Refer to the following figure.)
Piano keys 2 and 10 - Release the two keys to save your setting
and exit setup mode.
Bass end keyboard
Bass end of keyboard