Yamaha S30 only plays on Midi Channel 1

Hello,
I'm having trouble sending midi track data from Cakewalk Sonar Producer X1, into my Yamaha S30 Synth. ( http://www.vintagesynth.com/yamaha/s30.php ).
I can only get music out of it, if the track's midi channel is set to Channel 1, and the Mode button on the Synth is set to "Voice".
 
When I Use Channel 1, I am able to choose any voice or drum kit from the 5 Banks in the synth, so long as the midi channel in the computer's set on "1', and also that the "Voice" button on the synth is selected.
Normally, I assign all my track voices & channels within Sonar, and then go over to the synth and hit the "Performance" button, and it normally will play out all the assigned voices simultaneously.
 
Now for some reason, only Channel 1 will play from the computer. I've done a "Factory Reset" on the synth but that didn't help.
 
Has anyone had a similar experience?
Are there special settings within Sonar that might be missing?
I would appreciate your recommendations.
 
TIA.
 

Hello again.
 
Well I've found something weird.
When I was trying to play out multiple midi tracks, I was just using midi channels 1 & 2, whilst the the synth was in Performance mode.
But now I have found that all other channels EXCEPT CHANNEL 2, are working fine. WTF!
Only my midi channel 2 is dead. I've deleted the Instrument Definiton as re-imported it into Sonar, but still my midi channel 2 wont play. Maybe there's a problem with my synth. Investigations will continue.
 
Thanks anyway guys.
Adrian.