yamaha DX9

I want to use my sinth as controller for my PC's programs.How can I turn off the SYSEX of my sinth yamaha DX9?

If it's like the DX7 when you press button 8 in the Function menu (that's unmarked of course) you get a screen where you can toggle SYSEX INFO AVAIL/UNAVAIL. Try it and see.I hope that addresses your question.mn

Thank you Mike. I've tried but not successful. It seems like if the synth send continually a midi signal and it overloads the midi input of my audioboard. That is: after few chords I cannot play nothing else.
Ciao from ITALY