Quoted from dapperdan24:Would an issue with the pot affect only the music fx and not the sound fx?
No.
See pages 35-37 of your manual. Use a logic probe starting at connector A6P1 and follow the data signals 1-9 to see where they stop.
I just fixed a no background music issue last night on a Raven System 80B sound board by replacing G5. The AND gate output on G5 pin 6 was reading low and should have been high.
No background music could be several things but its all just guessing unless you use a probe.