Quoted from PinballTilt:Has anyone had to trim the foam in the chest? At first my game was fine, then the chest release wasn't opening enough so I bent it some. Now the balls aren't rolling, I think due to the foam. I was going to trim a little off with a scalpel or razor blade
I experienced the same problem after a few games with the chest not releasing balls. I learned that the pulsing of the star map magnetized one or two of the balls rapidly. I observed the chest mech opening and the ball struggling to get out or not rolling due to them sticking together coupled with the chest being on a ever so slight incline. It wouldn't do it all the time depending on which balls was in the chest. I changed the balls and the problem would go away for a while until one got magnetized again. The long term fix is carbon steel balls. I have had no problems since. The easiest way to adjust the release is slightly bend the bracket that holds the coil. The sweet spot is when it opens enough to let a ball out but on a 1st locked ball doesn't roll right through it. I wouldn't recommend trimming the foam as it guides the ball through the release arm.
Good luck hope you fix it.