Quoted from GRUMPY:

Lets recap here..
1. Both switches on the pop are open and the skirt moves freely and pops back to center.
2. Coil has 4 ohms resistance and a good diode installed the correct way.
3. Coil sleeve isn't melted and plunger moves up/down freely.
4. With connector 1J19 removed, connector 1J18 pin 4 measures 5 volts when game is on and in attract mode, then measures 0 volts when the skirt is pressed.
5. With power off and connector 1J19 removed, pin 6 reads open to ground on an ohm meter.
6. If all of this passes the test then there is a board problem.