Hi Kevin, The footswitch is basiclly just an 'off/on' switch (like a light switch)...so you are probably correct that it is the jack giving you the problem. Just to make sure....many pedals have a 'switch' on them, that can reverse the 'open or closed' action of the pedal. Like if it is normally open contacts, pressing the pedal will close the contact, or the reverse...if the switch is put on the other setting. That switch (if you have one) could be the problem. The jack is most likly 'mounted' directly on the Casio's circut board...and could have a loose connection ( a touch of a soldering gun to the connecting points would fix that), or the metal piece that contacts the 'tip' of the footswitch plug could be bent. If it is bent....you may be able to add a little 'tension' to the jack (by finding a small instrument to reach in the hole, and bend the metal piece toward the center of the hole.That would be the easy fix. The last option would be to replace the jack (you would need to find one with the same shape connecting points). Hope this will help you.