If you don't have a manual, d/l one from the IPDB. Then run the coil test, and see if the coils firing match up to the coil numbers given in the manual. Report results...

What actually fires, vs. what should fire, helps diagnose what line(s) are having a problems. The info comes over from MPU on connector J4, lines 1-10 (or so), as a binary number. If one or more lines is missing, the number gets messed up. For example (these numbers are made up) if 0011 is the number for bumper 1, but the LSB is always missing, the number seen by the SDB will be 0010, and will fire the wrong coil, and continue to fire wrong coils for all that need that bit.

Soooo, you could make a little table of what coil fires, vs. what coil should fire, consult the schematic (d/l the EBD one, it has the schematic), and find which line(s) are busted.

Or maybe this is overkill. You might get lucky by messing with the MPU j4 connector, and see if that helps--make sure it has solid continuity on all lines, etc.

But if a chip is causing the problem, then you'll need to dig further...

Cut the small disc capacitors off of the switches and see if the phantom reactions go away.

From the description of the problem, these are not 'phantom reactions' but incorrect solenoid firings in response to switch actions. I get this problem when I have the wrong game selected on my Alltek - as this is a new machine to you are you sure the game roms are correct? And as has already been mentioned, connector issue?

I have had similar problems in the past. Assuming the MPU chips are correct and the connectors are good, this issue comes up due to problems with the switch matrix. I visually check each switch that has the capacitor and diode. If they are touching metal this will disrupt the matrix and the MPU switch responses. I`ve most often found the issue on the drop targets, tilt ball assembly and also coin switch area. Good luck.