Hey guys -
Have an SB-300 with an odd issue that I haven't seen any troubleshooting tips/guides for, and thought I would get ideas here.
My Q2 signal (the voice that is modulated through the volume stepper) was completely dead. I replaced U17 since that was my prime suspect, and was able to get ... interesting results.
Specifically, that second voice now will seemingly randomly be at 100% volume, or be completely dead. It does not seem to relate to any specific sounds that the game wants to play.
So I'm torn between a bad volume stepper (or driving circuitry) or the 6840 timer's bad?