If it is a switch, then start the machine with the PF down and the coin door open.. look inside the machine while the game starts to reset. The PF switch will be JUST touching and you should see the blue  arcing, you might be able to do this with the PF raised slightly and pulled over the lockdown bar resting on a block.. this way you will know where the switch is rather than having to go through them all one by one.. do this and it will be the last one.. always is..