Can you help me understand why these two specific wires needed to be added?

I believe I wound up with the original poster’s unit. Same issue.. works fine when the J16 isn’t plugged in. When it is plugged in the game turns on and lights up, but it won’t play and I can’t access the service menu while it briefly displays an error: Top Eject Device Malfunction.

From the original poster. He didn’t make any of the adjustments you advised him of, but says after talking to Stern they had him make adjustments to the pin and it all worked... but he doesn’t remember what those adjustments were.

Any thoughts?

On a side note, I was unaware of any problems (or this post) until after I tried to install it.

There is currently a wire in p8 connecting the two, but there isn’t a wire between the two for p12. Rather the p12 wire runs to the control panel that I mounted near the front of the box.