Korg DW8000, Mono/Poly, MS-20...

I'm hearing an audio "pop" or "click" on certain patches when I play, especially in the lower keys. It doesn't happen all the time, but happens enough to be annoying. I just got my DW8000 a day or so ago, and I'm thinking I want to get rid of it right away unless I can find an answer.

I was going to use it for some recording, but that noise in the audio prohibits that. Any advice before I put it back on Craigslist where I found it?

Thank you,

Eric