I have little to no experience with repairing EM games, but I'm currently trying to troubleshoot/fix an issue with my Gottlieb Jungle Queen. I'd appreciate any tips for how to track down the cause. Basically, everything works fine until the last player drains their 5th ball. At this point, the machine gets caught in an endless loop rather than entering the "Game Over" state as it should. Additional details:
- After draining the final ball, the score motor starts to spin and never stops
- The issue happens regardless of how many players were in the game (always happens when the final player drains their final ball)
- When it gets stuck in the loop, the P1 and P4 lights in the upper left of the backbox are on, while P2 and P3 are off (even if it was a 1P game)
- In a 4P game, the P1-P4 lights proceed through this sequence when the final ball drains: P4 off -> P3 off -> P2 off -> P4 on -> stuck (seems like each step of the sequence corresponds to one rotation of the score motor)
- If I manually trigger the "Game Over" relay, it breaks out of the loop and correctly enters the game over state (although the P1 and P4 lights remains lit in the game over state which seems abnormal). Game resets and works fine if I start a new game after manually triggering the game over.

After some more testing and poking around, the problem seems to have resolved itself, although I never really identified the root cause

I manually fired the game over coil using some alligator clip wires just to be sure it was firing properly (it was). After that I examined the OR-GR wire that links the game over relay to the coin unit and poked around the coin unit a bit to see what was going on. At that point I ran through a game again and the machine successfully transitioned to the game over state (P4 light still on tho, hmm). My best guess is that one of the wires around the coin unit was loose/flaky or maybe one of the contacts was dirty and my poking around jostled things back into a working state. Guessing I'll see the issue pop up again at some point but now I have a pretty good idea of where the problem is. Thanks for all the help/advice! (FYI, before this I switched the game to 3 ball mode as frenchmarky suggested and the issue still occurred)