There may be a simple solution to this problem. The below instructions are taken from the Genos Owner's Manual under Troubleshooting.
The master volume may be set too low. Set it to an appropriate level with the [MASTER
VOLUME] dial.
All keyboard parts are set to off. Use the PART ON/OFF [RIGHT 1]/[RIGHT 2]/[RIGHT 3]/
button to turn it on (page 48).
The volume of individual parts may be set too low. Raise the volume in the Mixer display
(page 86).
Make sure the desired channel is set to on in the Mixer display (page 88).
Headphones are connected, disabling the speaker output. Unplug the headphones.
Connect the footswitch to the appropriate jack.
Check whether the external speaker is connected and the volume control is adjusted
properly (pages 108, 116).
Hope this helps.
Mike