Korg Forums

I've had several keys either not working at all or reluctantly after pressing them several times in a row. Any ideas? Thanks!

Get the keyboard out, on the other side of the keyboard there is a flexible board where the keys make contact with. On the board there are rubber strips for making the contact. Clean them with pure alcohol, medical alcohol. Put them back and look if they work, if not repeat procedure. If they are not working after a few retries, you will probably have to replace the rubbers.

There is a repair kit available for this as well.
http://www.oaktreeent.com/Korg_Keyboard_Parts_Units.htm