Most of the light sockets connect to the common, yellow power rail.
Captain Fantastic common power rail (resized).jpg
Somewhere the yellow wire probably connects to the ground braid. The yellow wire is probably thicker than most of the other wire.

/Mark

Ground or Power bus?
GI or Controlled lamps?

do yourself a favor and take a pic of the grounding braid in question. a visual will help you get a clearer answer from the folks who know.

So it looks to me that's the power bus bringing power to each lamp. The BLUE wire is the Ground for GI, & the RED/Yellow seems to be the Ground for controlled Lamps...at least some of the ones I can see.
Since that's a stock image I can't really see where the power hooks in; Basically you just need to find some wires soldered directly to the braid. Technically speaking, it doesn't matter where it hooks in, as long as it's all connected. Usually it's at a couple of places along the route, but not familiar with Bally EMs.

.

This may have been covered but in my playboy what you’re referring to as the ground is actually the positive and each wire going to the bulbs is the negative. It is the negative that is switched not the positive

This game is AC for GI and most everything else.

There is a rectifier in there for a couple of coils.

Most of what was posted is accurate... To help clarify, GI and Feature lamps on most all EMs (and even a lot of 80's SS games) use AC voltage. There is no "ground" with AC voltage... Please stop referring to this as ground braid in an EM. It's simply braided wire in an em, not ground braid.

One wire that touches all of the lamps is ONE SIDE of the AC circuit. That side is refereed to as the "SUPPLY" side. It supplies each socket-ed bulb on the PF with the "supply voltage". (This side of the circuit can actually be seen on BOTH TABS of each socket-ed bulb because the bulb's fulfillment is also a wire, connecting to the other side)...

Anyway, the other side (aka the RETURN SIDE) on a controlled lamp is switched on or off in order to illuminate each bulb with a single wire for each bulb, typically a different color for each.

With General Illumination(GI), the bulb is "always on" because the other side of the circuit (the RETURN SIDE), is always connected. THAT wire is ALSO commonly "braided wire" stapled to the playfield. For GI, both sides of that AC circuit typically use braided wire. It's not "ground" in AC, it is known as "return".

DON'T CONFUSE THIS with the "GROUND BRAID" used in a game to typically link all the metal cabinet pieces together. That braided wire is not always the same circuit, but it MIGHT be... THAT wire is for EARTH GROUND. Seen as: Screen Shot 2022-09-29 at 10.08.21 AM (resized).png

In an EM, that COULD be used as the return side of the circuit but, that's not always true. In a SS (or EM) game with DC and AC voltages, it is typically used as the "DC ground" side. You can use your volt meter's continuity function to test this.

In an AC circuit, the other side, aka "RETURN" side is the side that determines if a bulb is illuminated. Use your meter to determine what is actually happening on your playfield in Captain Fantastic. On your game (an EM), when placing your black and red volt meter leads on a socket, you will see AC voltage when the bulb is on... but, understanding why that's true is also important. Don't forget you can test your supply and return rails using the continuity setting on your meter too. Voltage is not the only important concept to understand with pinball lamps.

The BRAIDED supply voltage wire/bus/rail on your Captain Fantastic game's playfield could very well use the same braided wire/bus/rail for the "SUPPLY SIDE" of the AC controlled lamps AND the GI non-controlled lamps. It likely does because at the factory, it was less wires.

Be warned, as pinball manufacturers made more complex games, the need to supply the playfield with more and more wires was a direct result of adding so many feature and GI bulbs to the circuit.

Wires ran so hot to supply the proper amperage(aka the "amount" or "volume" of volts) that, multiple and completely separate GI and feature circuits were now needed. That's why there are multiple supply wires and fused circuits to a lot of late EM and early SS games. It's also partially why GI was kept AC and feature lamps were made DC. It was so the incandescent circuits would not overheat. So, keep this in mind when swapping the playfield on a later EM like CF.