Quoted from Scosti:
Yeah, from what I can understand from what I’ve read, with Stern’s switch matrix that of one switch isn’t making proper
Connection, the whole remaining switches won’t work after that. Is that correct thinking?
This is true in the case of a broken wire and applies to all games with a switch matrix. Switches are wired from one switch to the other. When the chain is broken, all downstream switches will not work.
In this case, the first few switches in the row that work are on the Loki lock sensor board 520-6780-01. The first non-working switch is on the Hulk 4-bank drop target board 520-5252-04. Re-seat the connectors on both these boards. See if anything changes (probably not).
While you are looking at these connectors, notice the green with yellow wire in the connector. I suspect there will be 2 green with yellow wires crimped into one of the positions on both these connectors. If there is not, look for a loose green with yellow wire in the area.