From my experience Giga Fevers backlight brackets are easily dislodged. I've had 2 and BOTH upon arrival had 1 or more backlights loose.

The reels have to come out to put them back into place correctly. If you didn't take the reels all the way out I suggest you do so.

Just unclip the circuit board that runs the length of the reels on top (back) then each reel has 2 push type fastners (top & bottom). Then they just slide out. Once out make sure the white plastic backlight housing inside the reel is snapped securely in place. Then put the reel back and you won't have another problem (unless you man handle the machine or ship it again).