Korg PA4X where does four-pin wires go?

I opened up my cord PA4X to clean the pads at some of the keys were not responding properly. Unfortunately, the keys fell out of the case too quickly. There is a four-pin long wire connected to the small printed circuit board on the keyboard that got pulled out from the other end and I have no idea where it goes. I cannot find a plug-in spot for it. Does anyone know where this goes?