Vintage Synth Repair

Hi,

While not a real vintage synth, I recently got a used Korg KARMA and noticed that one of the "Chord Trigger Buttons" does not work and another one works sometimes, sometimes not.  I was wondering how difficult it would be for a novice to replace these buttons and where can I get a set?  I can solder fairly well and can usually take apart and put things back together but have no experience torubleshooting.  I'm thinking that the buttons just need replaceing due to wear.

Any thoughts or suggestions?

Thanks

Greg