I came across a JD-990 and It doesn't have a instruction manual, I don't know how to get it to play more than 1 midi channel at a time. Can anyone help me out. This thing has some real cool sounds and I'm anxious to get it up and going but this lil problem is holding me back. I got it in my studio set up with a Mpc 2000 and a Proteus 2000, thanx.