The lighted time display?

I have just recently had issues with the light display on the Bose wave/cd player that we have had for many years. I have always loved the fact that when it is dark (evening in particular, I have to have it dark when I sleep!) that the display turns softer so that it doesn't disturb my sleep. Suddenly the display works in reverse. It dims in the light and brightens upon darkness. Is there a way to fix this so I don't have to cover this every night so I can get to sleep?