Defective LED?
It is a hardware malfunction and most likely the LED itself. I have not been into one of these scanners to know personally how difficult replacing it would be. I'd be fairly certain you can purchase the replacement LED from RS Parts - You have to go to the store and they can order replacement parts for you.I used to have my LEDs all different colors like the rest of you, but then the red went out, and the blue & greens are all light blue, no more yellow or anything else. Sometimes the red comes back, but more often not.
The LEDs lasted about a year from purchase. Is there any sort of reset or anything I can do?