I have a Gottlieb Volcano (model 667, system 80) and in the A3-J3 connector on the bottom of the driver board, I originally thought somebody had removed one of the lamp ground wires. I was troubleshooting some lamps that wouldn't light up and the lamp ground that is supposed to be in position C is missing. I can make it work with a simple jumper but I was determined to find if somebody had removed or cut this wire from the harness.

After painstakingly going through the harness and checking continuity one wire at a time from connector to connector, and comparing to schematics, it looks like an existing wire was simply moved from one position to another. Additionally, the harness is in pristine condition with original wire ties, so it does not appear anyone has removed any wires, nor have any been cut off and left inside the harness. Now after moving the one wire to where it belongs as per schematic, it still will not function properly without a jumper wire.

Can somebody with any Gottlieb System 80 game, please post an up close photo of the A3-J3 connector showing all the wires going into the housing positions so I can verify visually?

Thank you!

Thank you frenchmarky and @jethrop!

You confirmed that my wiring is correct. Moving the "missing" wire into the correct location was the right move. From position A in A3-J3 into position C is what I did, just like frenchmarky's here:

frenchmarky's connector

It's a Gottlieb so I'm too quick to assume a connection issue. Turns out after I moved the wire, coincidentally, the stupid 74175 driver at Z12 started flaking out. Replaced and working.

frenchmarky & JethroP -

Does your game still contain the original single-pin molex connector A7-J8/P8 ? It's supposed to tie the ground bus bar in the cabinet to someplace in the head of the machine. Since the head of the machine is mostly wood, I'm trying to figure out where exactly it was originally tied to. Clay's guide says something about it originally tying into a lock plate in the upper-left of the head, but I have no "plate" there, and the locking mechanism is completely isolated by wood, so this location makes no sense.

Certain MPU, grounding, etc. electronic modifications aside, I'm trying to "restore" to original as much as practically possible.

Thank you.