Did a service call Owner said switch was warm. took out 60-70's erea swithch, found travler a little burnt screw a little loose, replaced switch checked out at both ends no problems worked fine. looked at something in basment and started home half way there got a call sparks from switch, went back I moved the swithc and pop!! took out switch could not get it to doit again cycled evey swithc in the room many times and nothing put swithc back in and cycled many times and nothing. any thoughts would be helpful. don't want to leve it somethings not right but I can't see it right now