When I play the sound come out distorted, like it untunes. any idea what is causing the problem? this is a for a Korg X50 and is only 2 yrs old. not korg Ma30

The manual is at:http://www.korguksupport.co.uk/upload/X50_OpGuide_E1.pdf if you don't have one. Try saving everything you want to save first if you know how to do that. Then initialize the keyboard. Follow the instructions on page 111 carefully. It sounds like you created an undesirable effect and accidently assigned the Pitch Bend Lock function to the effect. This parameter is explained on page 41 under Pitch Wheel Mod Wheel. Hope this helps.