1995 Mazda Millenia-Bose System

I have a 1995 Millenia with a Bose Standard System.  The radio will come on and all the controls seem to be functioning, but i am not getting any sound to the speakers. I understand that each speaker operates with it's own amplifier and someone suggested that an  amp has a blown fuse. But why would a blown fuse in one amp cause the other four to not work? And what are the odds of all 5 amps blowing fuse at once?  I just bought the car and I like the way the Bose system sounds with the factory CD changer. I am trying to keep from doing an expensive install until the first of the year when I plan on installing a Panasonic Tv/DVD combo with Infintiy Highs and mids, and JL Audio W6's in a fiberglass trunk enclosure.  If anyone can answer any questions, or has their own idea or diagnosis, I would be forever grateful. Thanks.