[Kenwood] Kenwood TS930S will not transmit in SSB

[Jim Dicso]

My TS930S will not transmit in SSB mode; RX is fine in SSB.  Both TX and RX work fine in CW mode.  
I suspect the audio circuit on the main board.  
 
I'd appreciate advice on where to look and what to look for (have a scope, meters, etc).   I'm hoping to get some advice on how to troubleshoot the problem and fix it without pulling out the large main board.
 
Thanks, Jim K2SZ