The issue I'm having with my JTV-89F, is that when my modelling function is turned on, several of the strings do not respond properly and do not have consistent output. I can assume this is an issue with the piezo. Is there a way to reset the piezo to respond properly? I don't have a reason why this happened as it worked one day and then the next, not so much. I have searched for a solution but haven't found a resource that pertains specifically to my problem. Any thoughts?