Audio Systems: 1992 ford sho car radio, blown fuse, buttons work

Question
The radio in my 1992 SHO comes on, all buttons work but no sound.  I bought another identical radio and put it in and have the same problem. Is there an external amp somewhere I dont know about?   Any thoughts?

Answer
Ralph,
Please give me the complete model number of your stereo, with the model number I can look at the service manual and tell you actually what and where the amp (if used) is located and where to look for a possible blown fuse for the amp.

TOM,
T&D ELECTRONICS
[email protected]