Was playing a game with my wife when suddenly, the game had a mind of its own. Tolls accumulating, points scoring, Jet bumper going off. Here are the current symptoms. Start a game and it will immediately, but sporadically accumulate tolls. The top right jet bumper (special solenoid) will also fire sporadically. If you nudge the game, even lightly, you can trigger the tolls and jet bumper. Diagnostics all fine except for coil test where the top right jet bumper will fire on any C-side test (in addition to the correct coil). I had an issue with the Top Right jet bumper in the past, so I checked and replaced the transistors and PIA in that circuit, even though everything tested OK. It did not help.
I disconnected all of the toll switches since it was an easy test but it made no difference. I can still collect tolls by starting a game or by giving a nudge. I assume it must be MPU or a short somewhere but am at a loss as to what, where and how to localize the problem. Another bit of info, which is probably not related, is that several weeks before this, my display started showing commas between every digit. Not always but sporadically. Thoughts on where how to track down the issue? Thanks