Alternatively, you can take the center coin switch wires (assuming unused - if not, any will do) and wire them straight to the switch in tandem with the existing switch wires. The common wire gets soldered directly to one switch lead, and the dedicated wire gets a diode in the middle before it heads to the other switch contact. This should coin up everytime you press start. I have all my Ballys wired this way. No extra parts needed, save a diode, and then perhaps a connector if you get fancy.