Hello + I hope this finds you well! Thought to ask about a bit of a riddle with a PCM-42. Have combed through it with the service manual and schematics, the unit works perfectly – except – it will not modulate. Can’t think of anything else to check. It's been recapped, pots are good, and all healthy otherwise. Sounds perfect, other than not being able to modulate. Wondered if anyone had ever seen this anomaly before, or had any ideas what part(s) to check on the board or which part is controlling the modulation. Thank you in advance for any leads!