Just a guess (I don't have this machine), but since it is close to the Coin & 25 cent Relays, it might be the Replay Relay. All 3 of those use 110v as opposed to the normal 24v used on the majority of relays.

No, the tilt relays are already identified in the picture. Pretty sure it's the Replay Relay. To verify, check if voltage is 110v and/or it momentarily activates when the start button is pushed.

Hi @rolf_martin_062,
You might be looking at something different than I am, but I see where someone spliced into a wire coming from the transformer and there appears to be black electrical tape on the splice (would be much safer to have a "splice cap" or as some people call it a "wire nut" on it). But I don't see any loose wires around that replay relay. You might have better eyes than I do though!

Edit: I read what you said again, and I think I understand now that you mean there should be an insulated, not bare wire, jumpered between the Coin Relay and the Replay Relay. If so, I agree.

Rolf,
Yes, I agree these older machines can be dangerous to work on if you don't know what's going on inside them. I would bet the bare wire is factory installation though - they daisy-chained relays together like that back then. You can see the all the 24v relays are tied together with bare wire in the same manner. Just the way they did things back then and I think that was because they didn't expect anyone but knowledgeable technicians working on them - not a lot of machines were collected in a home & hobby setting back then.