Quote from Clay...
Another hold style coil (though not a relay) are the flipper coils. If the player holds in a flipper button and the coils make a loud buzz, this can be often be fixed by replacing the coil stop. The coil stops on EM coils are slightly magnetic. This minimized the problem with the 60 cycles per second AC vibration.
I would take that to mean that the stops on an SS machine to not "slightly magnetic"?
Plot thickens...