Another question to ask. (And perhaps my experimentations with the Roland RS-09 and its gate voltage lead me to this symptom)
If you could test something on your Voyager and let me know what you get as a result, that’d be great!
Set-up a simple sound and check the following:
When you switch ON/External ‘on’ and ‘off’ repeatedly, do you notice that sometimes the sound is quieter than usual? Mine seems to jump from two states: quite and normal. It’s either full volume or at about 50% in reduced gain.
Let me know, I feel like I need to get my Minimoog OS serviced because it’s slowly falling apart.