91 stealth cd player

I have the above stealth with mitsubishi radio/cass and cd player (seperate head units) that is the stock unit. The cd player get power but gives me the letter "E" and ejects the cd. I've had it cleaned but it still doesn't work. Before I spend anymore money on getting it fixed, is there anyone who might have and idea if there is anything I can do before I send it away. I was told maybe there is a reset button on the unit. But, I see none. Thanks.