Scanner screen (by 3 users)

My scanner developed a thin green line down the left and a broader yellow line down the right; they both increased in width until I was left with a space only large enough to scan a postcard. I would let it rest after about three scans and could get the narrower bands back. Today I went to use it again, but this time the entire screen was dark green and, unlike the earlier banding, not even translucent. The lamp is on, no less bright than as new, and it moves as it should.