Hey, I just got this old 78 saab, it has an alpine stereo in it, not sure what kind yet. There is an "E" on the display thing, and it wont play anything. The guy I bought it from tried to disconnect and reconnect it from the battery and power numerous times to get it to work. But he thinks the "E" happened because he forgot the passcode and accidentally typed the wrong one in three times. HOW DO I FIX THIS? someone please help. thanks a ton.