Kenwood Problems, No Sound.?

I recently had a Kenwood KDC-138 installed into my 1991 Honda Accord, everything on it checks out as far as the functionality of the faceplate... The issue is that I can turn the volume all of the way up on it and no sound will play. Did I get a bad installation, would it be possible for a rookie to fix it himself?? Any advice will help, thanks!