No Image, blank black screen
Black screen one side: Failed LED backlight, contact support for repair.
Black screen both sides:
With the battery connected the display should either show snow from the receiver (if enabled or turned on) or at least show a "glowing" black background.
If the display is completely black, then it is likely due to no power being supplied to the headset (i.e. battery dead).
To Test: With power supplied, press the channel select button or rocker and change the channel up or down (doesn't matter if any receiver is installed or if receiver is turned on - beeper will still function).
1) If no beep on channel change then its a power supply issue. Check battery (possibly needs safety switch reset - see section on battery). If not using battery, check cable and connections as well as correct polarity.
2) If beep then LCD driver may have failed. Contact Fat Shark support for assistance.