I had the same issue. Chaser Lamps and Coin Door lights not working. I had 5v at the Sound Overlay board. My fuse was also good at F2, in fact all of the fuses were good. At some point in time someone had replaced the F2 fuse holder. The glue they had used to hold it down was no good and the fuse holder was just floating in space. I've seen fuse holders like that before. A continuity test "worked" but not well. It took some pushing down for it to prove that the wire from the fuse holder to the board was good. Long story short it was a bad solder joint at the F2 Fuse holder... I reflowed all of the headers while the interface board was out. Of course I did also replace the bridge rectifier on the Sound Overlay board first...and that did nothing. It tested odd in circuit and had some values that took a while to lock in when tested out, so I figured I'd just try replacing it. But the bridge rectifier wasn't the solution. It was the solder joint for the F2 Fuse holder. There is evidence that F2 had burned out at one point in time.

Coin Door lights and chaser lamps are considered part of G.I. so that's probably why F2 was the culprit. The other place to look would be the connector at J9 on the interconnect board. That connection goes out to the coin door lights and will turn on and off the chaser lights. That same connection also goes back up to the Sound Overlay board.

Thanks for posting this eons ago!