I have a passive component on my power supply. Component looks like a disk capacitor and is marked "222". It has three leads, the outer two of which are insulated with rubber/foam. I'm not sure what this component is. I thought it was a thermistor, but can't find a thermistor with three leads. My keyboard suddenly died, and I think this part is responsible, but I can't find the part on line. Any help would be appreciated. Thank you. Fred