Quoted from ExSquid:Just pull on it a little bit without taking it off? and to make them more sensitive do I just have to close the gap on the leaf switches a bit?
The sling mech is behind the rubber band. If too tight, the ball will not activate the sling mech switch and not push the ball into the pop bumpers. Just grab hold of the rubber band and give it a tug away from the sling mech. It will loosen the band and the weight of the ball will activate the switch behind to rubber band.
If you need to make a switch adjustment, you will need to use a tool to reduce the gap of the switch. Pop bumper switches are sometimes finicky but are rather easy to adjust. You will need to lift the playfield for those. A switch that is too sensitive may cause the same effect by not working well so play with the gap a bit to find the sweet spot.