That’s really good information to have…the high side audio is not pulsing (thanks for the audio clip, that was very helpful). The other piece of good information to know is that the high optocoupler LED is working. So there must be a problem around the LDR, like it’s possibly shorted. So from looking at the schematic, make sure TP1 and TP2 (or JP1 and JP2) aren’t connected/shorted. You can use your meter’s continuity tester to check this (with the pedal’s power off).
Let me know what you find.
-Brach