I have had an Alpine head unit in my car for the last 2 years. The unit is about 4 years old, and was given to me by a friend when he purchased a new car. It has a motorized face plate, and runs 60 watt per channel. Lately, when I try to put a cd in, the tray opens, and an error message comes up. It will then not close. The error message also appears when I just press the cd button. I was thinking that it may just need to be cleaned. Has anyone else had this problem? Thanks.