Hi Norman,
on all PSR-S/SX models, the Mic/Guitar input is unbalanced, i.e. only TS plugs are supported. (You can also use a TSR plug, but then the Ring and Sleeve contacts must be bridged.)
To connect a standard (balanced) microphone, you have to use an unbalanced cable (XLR female to TS) with XLR pins 1 and 3 bridged.
Best regards,
Chris
