Hi feivi18,
in this case, there is NO need for a System Reset!
Only the MIDI Setup is set wrong. Probably, a MIDI Setup is activated actually, which has a special setting for listening to a Bass note on a particular MIDI channel (e. g.
Accordion or
Pedal). And if NO Bass note is received on this special MIDI channel (from an external MIDI instrument), the accompaniment always plays a
C as Bass note.
To solve that problem, please press "[FUNCTION] ---> Tab MENU 1 --->
MIDI", activate the MIDI Setup "
All Parts" and press [EXIT] to close that display.
Hope this helps!
Best regards,
Chris