I have this, and have just installed it, so I'd like to go through the manual, but I haven't been able to find it online.
What I see when I have just the transformer board & solenoid driver board plugged in is 3 green LEDs in the upper right, and 5 green LEDs in the upper center that spin in a circle; I have no idea if this is good or bad news, although presumably green means good. Since I am having problems with a new replacement transformer board on another Bally, I am being very, very careful, and doing board plugging-in very step by step - so I need to do this before I plug in the MPU.