J136 is a drive for Column 7+8, that is Yel-Vio (J136-2) and Yel-Gry (J136-3).
That means if that connector with Yel-Gry and Red-Gry is put on J136, it will indeed get haywire.

I do not know JudgeDredd well enough to say if there should be a connector in the backbox connecting the Red-Gry and Yel-Gray ( sw.#88) to the startbutton, but you might expect such thing.

J136 is typically used for controlled lamps in the head, pins 2 and 3 of this connector are directly tied to pins 7 and 9 of J137 and 138, since they are the same point, introducing another signal onto these points would cause unexpected lamp matrix behavior.

You may want to look for a two pin female connector somewhere else in the head that this cable is supposed to connect to.

That cable in that photo does not look like the right type of cable for that connector at all. It looks like someone pushed it in there when it shouldn't be.

Cabinet button lamps (start button, launch ball button) often comes off of J136 too.

It can get confusing because you have that little plug for the yellow wire(s), but the red wire(s) go on a normal size plug on J133/134/135. In your case, the cabinet red wires are actually plugged into J135.

Yesterday I had a look into a JudgeDredd and took a picture.
This is a parallel connection to the startbutton lamp, but no contra inside the backbox to plug in.
I guess it can be used for topper or behind translite to flash simultanious with startbutton.
lmp-mx_88.jpg

zaza, I have the same connector in my JD.

I have noticed that it causes some weird behaviour in attract mode. When plugged in, the Super Game and Extra Ball buttons will flash during attract mode. When left unplugged, the Super Game and Start buttons will flash in attract mode. Since B/W Williams games are supposed to flash only the Start button during attract mode, I have to assume that it is best to leave J136 unplugged. I would be interested to see if anyone else notices this behaviour on their machines.

Edit: on further inspection, with J136 plugged in, the Extra Ball button does not flash at a consistent rate like the Start button does. It flashes in sync with the insert lamps on the playfield. Weird!

Okay I had the Lamp Matrix going nuts and tracked it down to this mystery connector being connected to J136. I still have not yet read what the purpose of this connector is.

Is it safe to "assume" that this is just an auxiliary connector that came from the factory, and it was connected to nothing?

Yes.

LTG : )

It is my understanding that the connector in question was for lighting expansion in the head of the machine that never happened. It must have been pulled from production.
That connector just hangs in the head with no use.

My Twilight Zone has a factory connector at J136. I have been playing with it disconnected, and noticed it while looking at another issue. I will see if I can trace where it goes.

Lamp #87 buy-in button
Lamp #88 start button

J136 for Twilight Zone and Theater of Magic is for the Extra ball switch light, (buy in). Oops, did not see previous post, thanks.