Yamaha Mark IV Operating Manual page 12

Note:
In case the Disklavier and the Tablet Controller cannot connect in wireless, the
following display appears.
If this happens, either the Disklavier is turned off or the Tablet Controller is out of
specified operation range.
Note:
It takes several minutes to turn on the Disklavier. So if you turn on the Tablet
Controller and the Disklavier at the same time, the above display may appear for a while.
Once the Disklavier is turned on, the above display will be changed to the standby display
automatically.
Standby display
Chapter 2: Basic Operations
11