Some general hints here

Touch certain points on the RF-board with a multimeter test-cord, a piece of cable or similar. A test-cord with measuring tip is well suited for this. Please listen to auio out (speakers or head phones) while doing this.

If there is no sound when touching the base of Q1 there certainly is a hardware problem. This could also have something to do with the mixer or local oscillator. In case there is also no sound when touching the collector of Q1then this indicates a mixer problem, an issue in the subsequent operational amplifier or or in the audio codec including its switching mimic. Since the signal path after the mixer is low frequency audio this can also simply be verified by touching with a finger for initial empirical testing.