Quoted from nosro:On my machine, the ball tended to fly through without hitting any of the pops. I replaced the post sleeve above the Zuse pop with a Williams post sleeve, which I discovered is thicker than the Stern post sleeve, altering the behavior so that the ball is now always diverted to the pops.
I did the same thing to mine. Used to fly straight through and into the center drain; now deflects into the pops.