Get a Ketron? Please read my post in the Ketron forum, I have been having the exact same problem with my Ketron X1 for few months!
http://www.synthzone.com/ubbs/Forum22/HTML/000702.html It looks like an Italian virus that hits all boards made in Italy! (I know the Korg arranger line is made in Italy). Just kidding

Thank God I didn’t have to fix my X1, it’s working fine now without me doing anything.
My advice to your friend, Plug and Pray!
Maged