This means the problem is not in the LCD, it’s somewhere else. Perhaps the LCD contrast value has been changed for some reason. Try to perform a reset: turn off controller, press and hold button B3 while plugging in a USB cable (or power the controller on), do you see any display text? If so, click B3 until you see the ‘Reset All?’ option, and click B1 or B2 to select Yes. Then press and hold B3 until the unit restarts.