That's a ground mod.

Gottlieb system 1 and 80 series didn’t have grounded boards, the only exception being Alien Star. This lack of grounded boards caused electrical shorts in games. It’s a recommenced modification per pinwiki.

Albeit, poorly done.

Exposed wire shouldn't be left swinging in the wind.

That should be spliced and heatshrinked properly, or the whole wire should be redone. I'd probably redo it.

The dude who did it couldn't scramble up ONE lousy foot & a half piece of wire, he had to splice three different scraps together, one of them only an inch long? And then just solder it to a capacitor lead and a top trace right in the middle of the board and no insulation on anything. GeeeEEEzzz!!

I was thinking he used boards that already had ground mods from different machines and the ground wires were too short for this machine, hence the jumper to connect.

Clay's guide recommend soldering to the cap and the trace in the middle of the board. It doesn't recommend using a bunch of wire scraps.

I cringe a little when I read a for sale add on a system 80 that includes the phrase "ground mods done." This is what they are talking about.

I've only done it once and used the guide, on my BH, but where I was able to I made the connections using lugs at ends of the wires and then bolted them on (two on power board ground plate and one at center of CPU board). Figured if I ever needed to pull a board to repair something, the bolted connections would make it easier. Luckily I have never needed to do that anyway. But I guess would be just as good to solder all the wires but add connectors to the wires so you can unplug them.

It's not that the boards weren't grounded, it's that the ground goes through the connectors. Most manufacturer's used a grounding plate and ground thought the screws that hold the board in place. Because the connectors are unreliable in these games, pinball folklore suggests that the best way to improve reliability is to solder a bunch of extra wires to add more paths to ground.

Gottlieb built some amazing games, but they had a tendency to overbuild and created some unique issues that aren't in other games.