After watching 2 YouTube videos. It appears that the pops light with the switching of an alternating relay. When the lower right lane light is lit the pops should be lit, except the 1000 point pop (maybe). When the ball hits the pop it should light the pop bumpers. As for which alternating relay, you are going to have to check a schematic, or wait for another Pinsider reply.

Have you checked if the light bulbs in each of the pop bumpers are good?