You should look at the switch matrix diagram and see what other switches are in the row and column shared with that drop target switch. A broken wire somewhere else in the chain of switches going to or from the backbox could cause that switch to malfunction.

If all look good, then press the drop target switch closed and measure continuity between the two metal lugs on the switch with your multimeter. If that shows a good connection, then it could be that the connector going to the board needs to be re-pinned.

Just some thoughts. Take a closer look and report back.

I would desolder and remove the wire, clean the lug, and cut and strip the wire so you can solder a fresh piece on. See if that helps.

Well, if you own a pinball machine, you are going to have to solder something at some point. 6 years ago, I didn’t know how to do anything, and was paranoid about messing stuff up, so I get it. That said, you need to learn as I needed to, and soldering a wire on a lug is one of the easiest things to solder. Too bad you’re in a different state and there is a global pandemic, otherwise I would come over and show you how. I’m sure there are lots of pinsiders in the Chicago area that would be glad to help if there wasn’t a pandemic.

I would suggest watching a few YouTube videos on basic soldering. Perhaps practice with some spare wire outside of the machine. Then give it a try. I would also be willing to FaceTime with you and walk you through it, but that might be difficult to get the camera in the right position while you’re holding wires and a soldering iron.