Set it to an analog conventional channel, like a weather channel, and set squelch to 0 and volume halfway up. Then wiggle the speaker plug and se if you can manage to get any kind of sound. Try also just having the connector halfway in as the internal speaker might then come to life. If it's totally dead then the speaker amplifier could have died. Check that the settings for tune mode do not have any of the digital modes checked and then enter a frequency to test. I assume that there's no keypad beeps or anything and that the display indicate that you receive conversations?
/Ubbe