Your display may be off for a number of reasons:
If you have selected the Backlight setting to be Timed or Off, then the display will be blank when you are not using it (or it is scheduled to be off). Press any button and the display
should come back on.
See ‘Backlight’ on page 17 of the manuals for more information on the Backlight setting.
If the display is being powered by batteries, then it may be that they have run flat. Either connect your display using the supplied power adapter or change the batteries.
The display will run for approximately 72 hours while on batteries so that you can carry it around the home to learn how different appliances work. It is not intended for prolonged use.