Quoted from newovad:
So, mid-way through ball 2 today, I hear something firing that shouldn't be. Put the ball in the scoop to start a mode and it shoots it right back at me. Get it cradled and pop open the coin door. Sure enough, left scoop is firing. However, it is firing to the beat of the music (I think it was the end of Stampede). That mode finishes and things are seemingly back to normal until the knocker starts firing during the current mode.
I have unresolved issues with the flashers that are listed in parallel with knocker, left scoop and ball release. (Data East L/R deal). So, should I be looking at the Q39-46 transistors? I saw an old thread about unwanted coils firing but no replies or solutions.
Have you probed the switch drives and returns on CN8 and CN10? Verify the drive pins are all pulsing and verify the returns have voltage present as well. If that checks good reconnect CN8 and CN10, disconnect CN11, CN12, CN9 and then go back into active switch test and try every switch to see if they are shorting multiple switches when one is pressed.