Look at the price guides and other ads here in pinside. Also, why not place an ad here in the classifieds?

Diodes are use when there is a switch matrix. You have two wires attached to that switch, but those wires are also attached to 7 other switches. When you close a switch, current flows from + to -. A diode acts like a One Way valve allowing current to flow in the proper direction. When another switch in the chain is closed, it can backfeed current the wrong way if that diode isn't there.

Edit: found this guide that explains it in more depth:

https://www.flippers.be/basics/101_switch_matrix.html

Getting ready to dive into a problem with my trunk that started yesterday. I turned it on to play and at some point it started missing the stopping point and sometimes seemingly gets lost. I went into trunk test mode and sometimes it works, sometimes it misses and stops 10 degrees off or so and sometimes just keeps spinning in 360 degrees not stopping anywhere.

Before I start really digging in, have any of you seen this behavior? Trunk sensor board? Connections?

Edit: trunk has the metal sensor ring and it is not cracked or anything.

Thanks!

Thanks! I thought cleaning it might be the first thing to try and makes the most sense before I start replacing parts. The ring is definitely not loose. I had the playfield propped up so I could cycle the trunk so I could watch the slot and the behavior.