I have an old Yamaha HC2 organ which has served me well - and is still going strong! It dates from around 1990, and only has fairly simple MIDI capabilities. The upper manual outputs MIDI data on channel 1, the lower on channel 2 and the pedal board on channel 3....So...I thought I’d try an experiment which has turned out pretty well - except for one thing…

Selecting some of the MOX tone wheel organ voices - which are way better than the original ones - I can now play the organ console using MOX voices. The problem is with the rotary speaker control.
To try things out, I selected an unused pattern location, and selected one voice (Slow Jam) for track one, and another (Left Manual) for track 2. I used the mixer to set the levels of the two voices.
Works very well… but… I can only control the ‘Leslie’ rotor speed of the channel that the MOX has currently selected with the associated track button.
I have the assignable foot switch set to duplicate the mod wheel function, but the attached foot switch only changes the speed of the selected channel. The other unselected channel - (either 1 or 2) retains the last set state (either fast or slow).

I can play both manuals at once just fine, but can only change the rotor speed of the selected channel. How can I get both channels - 1 and 2 - to respond to the foot switch (mod wheel) command... that is both the selected and unselected track.?...
Any tips greatly appreciated…