I realize there are a number of Ghostbusters issue threads open, but I felt this was important enough to flag separately so no one misses it.

When working on the playfield, I realized the area on top of the right magna sling was extremely hot to the touch. It turned out that the slingshot switch gap was default closed and the coil was locked on. It was subtle enough that a ball strike would still bounce the switch to fire the ball and look like it was working correctly, but steady state was locked on. In retrospect, I had a bit of weird ball behavior around that area (occasional spins, etc.) but not enough that I was able to make the connection that the coil was locked. Luckily, I was able to catch this before any visible playfield damage occurred.

Certainly a risky failure mode, especially on a location game. If anyone wants to make a set of these with the right connectors and appropriate fuse value, I'm certainly a buyer: http://www.pinballlife.com/index.php?p=product&id=1170