I do repairs on different gear pretty often and a friend of mine dropped off his microkorg that’s been having issues with noise in the audio outputs and headphone jack. It’s definitely seen some abuse over the years, but besides the usual wear and tear there doesn’t seem to be any other issues with it. What’s confusing me is that the noise issues are on most of the presets, but a handful of them sound perfectly fine and there’s no noise whatsoever.
To be honest, I’ve never used a microkorg until today so I am unfamiliar with the settings and how to navigate other than what I’ve figured out in the moment such as switching between presets. That being said, the noise is significantly louder than the sound of the keyboard which is audible but much lower volume and difficult to discern amongst the noise. It’s on the line outputs and headphone output and so far none of the parameters I changed made any difference. I know it’s not an issue with the cables or my headphones since some presets work perfectly without any noise and I used the same cables and headphones with other gear to confirm and didn’t have any noise issues. Wherever the noise is coming from is in the signal chain somewhere right before the master volume because that’s the only control that seems to have any affect on the noise. There’s also a few patches where the A side will have that noise but the B side doesn’t and I can’t seem to make the noise “appear” where it isn’t already audible and can’t make it disappear whenever it is audible.
This was bought used and there’s no way any warranty on it would be valid anymore so sending it back to Moog would come out of pocket. I’d like to fix it myself as a favor for a friend, so I’m just hoping that someone here might’ve experienced this issue before and found a solution or maybe have some ideas as to the cause of it? Anything I should try to help narrow down the problem area?