Last night I switched out the op amp. Voltages are now reading at expected values. However, still no sound, so on to round 2…
I can now trace the audio path back to the output pad for C22. The output from here contains both the wet and dry signal, so we are definitely making progress! The is no output from the input pad for C22, nor from any pad before it. I measured continuity between the input pad and C22, and it is open. I also measure resistance between the two pads on R20 and there is none. This seems potentially problematic (doesn’t that mean my input signal is going straight to ground?). However, I am still figuring out how everything in the circuit works, and know that you can’t get reliable reading when measuring components on the board. Additional suggestions would be welcome- I’m getting close!