If the light flashes in time with any MIDI input, then the MIDI data is getting into the SD2 but no Audio is coming out. Using headphones is a good test, so you have done that and still no joy. There might be a situation where computer software or you hardware MIDI controller may have sent a CC7 of zero...

First thing to do in order to check it out is turn it off, wait a few seconds and turn it on again. The SD2 performs a full reset routine on powerup.

If still no joy, try eliminating the computer temporarily, if you have a MIDI keyboard, hook its MIDI out directly to the MIDI in of the Ketron and see if you can hear it in the headphones.

I'm assuming you already made sure that the SD2's Volume slider is turned all the way up to the right...


--Mac