I would like to modify some of the organ settings on the Korg SG-Rack I just got (which has sounds identical to those on the SGProX keyboard), and am having trouble doing so. I want to take out the overtones in the "R&B Organ" organ program, and turn down the overdrive or distortion that's on the "Perc Organ" program. These effects don't turn off when I push the "Effects" button.

Does anyone know how to adjust these effects? Thanks!