Audio Systems: Delco AM/FM Cassette, chevrolet z71, radio feed

Question
I've got a 92 Chevrolet Z71 pickup.  The AM/FM cassette has suddenly stopped working.  All displays are lit, (clock and radio), however, nothing is working.  Stays stuck on same station. Have already checked CTSY fuse and radio feed fuse.  Both are good.  Any ideas?  

Answer
Hello Chris,
If you push the power button and the stereo still turns on then both power feeds are still OK. Usually when a radio won't tune or allow any other function to work, it signals some kind of main processor fault. Please contact me direct for more details about your stereo.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net