Unplug the unresponsive device from the AC power outlet.
Remove the Philips or Torx screws securing the top or side panel of the device to the remainder of the chassis. Pull the top or side panel off the unit and examine the glass fuses.
Look for smoky or black coloration inside the clear glass body of the fuse. If the body of the fuse has a white or almond colored body, pull the fuse and replace it with another using the fuse pullers.
Snap a new fuse into the metal "C" shaped brackets. Replace the top or panel of the unit. Plug in the device and test for normal operation.