I was using an air pump that plugs into the cigarette lighter to add air to the tires on my 1989 740 GL wagon and blew fuse #14. Apparently the radio was on at that time and I probably overloaded the circuit. I replaced the fuse and the air pump worked again. The radio however did not. The radio/cassette player model TR-6141 seems to work in all respects, that is the preselects work, the tape player works, the digital clock works, the antenna goes up and down however there is no sound.

Is there a way I can tell if the problem is in the radio/cassette player or the amplifier? That is, which unit needs to be replaced?