Quoted from beefzap:1) How to reduce drains through the pop bumpers
Make sure the game is level side to side and at about a 7 degree pitch.
Quoted from beefzap:2) How to reduce drains off the barn magnet. Sometimes the magnet does not activate long enough and the ball just goes sits there then SDTM
If you hit your flipper buttons a few times, it will usually cause the magnet to pulse and keep the ball from draining SDTM.
Quoted from beefzap:3) How to improve the detection of the switch on the zombie head in the barn so all hits are registered.
You should be able to adjust the switch gap to make it more sensitive.