Changes

You can test the PSG sound channels with by typing simple SOUND commands in BASIC. You should hear a 440Hz sound for 10 seconds at full volume for each of these commands:

SOUND 1,440,1000,15 should produce a 440Hz sound for 10s in the left speaker. (channel A) SOUND 2,440,1000,15 should produce a 440Hz sound for 10s in both speakers. (channel B) SOUND 4,440,1000,15 should produce a 440Hz sound for 10s in the right speaker. (channel C)