Hi, Derek -
Make sure you are in EXPAND MODE and you have VOCALIST set to ON. Your mic slider volume control on the left side of your keyboard should be set high enough for the mic volume to come through.
RMempstead, what "mic switch" are you talking about that needs switching on? I know of no such. Turning Mic on, on the right side of the keyboard has nothing to do with the mic working. It is only for effects.
Derek, if your present mic is a low impedance mic, it needs to be changed to a high impedance otherwise, it will not work.
Mark