Hi cperro
I do not have the schematics to Gottlieb Slick Chick. I show on "Ice Revue" - see the many switches and the wiring on the right side in the JPG --- maybe not good connection. Just to test the bumper action You may set "permanent jumper" (see left side of my JPG) --- does the bumper action improve ?
You may do "jumpering on the powerside connection" BUT MAKE connection after start / reset. And this "jumpering on the powerside connection" You only should do for a test --- to learn about "is the powerside-connection in the pin of not so good quality (?)". Greetings Rolf