Dead amplifier or ???
If you're so inclined, you could determine if the power amp (& speaker) are the problem or something before that. Just opening the scanner you might smell something burned, or see something burned.
You can get "full volume" audio "across" the volume control pot. Connect this point to an external amplifier line input (with the squelch wide open) and see what you hear. If you hear something, you know it is just the audio output stage. Note I have seen headphone jacks fail before such that they kill audio to the speaker and to any headphones connected.
If you get no audio from that point, the next circuit backwards is usually the squelch. But that does depend on the exact model, etc of your unit.
Good luck,
George