Had a major break through on this over the weekend!!! I was having a hard time figuring out why the signal wouldn't trip the coil on the relay, the DMM would beep from ground to open, but the relay wouldn't go. Just by chance I decided to put a LED in the line to see if there was any juice going through the line; as soon as I added that the relay started working. So I have a wire coming off of the CPU board for Solenoid #15 - going through a 1N5404 diode - THEN going through a 10mm jumbo LED I had laying around - into the trigger for this relay: http://www.amazon.com/gp/product/B00GWFCE0Q
I powered the relay directly off the power boards 5V & ground - Ground also to the COM and the motor's ground to the NC.
I didn't have much chance to play, but the shaker is going with the pop-bumpers, center VUK (earthquake), shark VUK & right ramp so far that I noticed.