4 player Survival/Pong game, can't start 4 player mode

[Vilepickle]

Recently purchased an old 70's 4 player pong cabinet. The game says it can play 4 players if you have pay mode on. However, it's on free play. The start button starts with only 2 players with no clear way to start with 4. Anyone know a way to get 4 players on free play? I have some instructions with it that talk about removing a trace and adding a jumper on the game board to turn free play off, but nothing about the 4 players with free play on.