I had crossed 2 sets of connectors late last year. For those that aren't familiar with WMS games of this era, there are a set of white and black connectors, and I put a black one with a white one and killed my MPU. I had the board repaired by Jerry Clause (great guy btw) and the game has been running mostly good for the last 2 months. The one thing that happens when starting multiple player games is that every time I press the Start button to add players, it also adds points to Player 1's score. It will do this even after 4 players are added. I couldn't tell you the exact value, and the value seems like a random amount (not always 5K or whatever).
The other issue I sometimes see is that in attract mode or sometimes (more rarely) in the middle of a game, the game will lock up. Everything but the GI shuts off. On the diagnostic LED on the MPU, it shows error code 7. I can press the sound test button on the MPU and it'll make a sound, afterwards I'll press the other diagnostic button, and it'll change to error code 5. Then a quick shut off and back on and the game will boot back into attract mode. This has been happening after the MPU repair.
Thoughts on either issue would be appreciated!