One of the first things to do to that small driver board is to find the ground on it and solder a big fat wire to that and tie it to the backplane ground. The factory wired ground to that board goes over to the far left side of the main driver board and is 1 or 2 wires on an IDC connnector there. It that ground connection there gets loose it will wreak havoc on the ball shooter coil transistor and possibly the auger motor. On my first hyperball (i think I've had around 7 by now) that ground was loose so that caused the fire signal from the MPU board to float and this made me burn up around 4 or 5 of the shooter coil transistors ($10-$15 each) before I located the problem.

Those 2 devices get their CPU signal from the two small transistors (2N3904?? I forget exactly which) on the middle right side of the main driver board. Start there to see if the signal is making it from that driver board over the the small driver board.