Im still leaning towards a switch in put issue here.

Could be the female connector thats at fault as then boards would be OK, but not read one of 2 switch closures.

Game scores when drop is down... OK.. that side works OK.

But game either does not read all are down or cannot do anything about it.

The fact that your coin door switches are doing nothing also suggests to me that maybe the 3 drops down is not being read at CPU.

The coin door switches have nothing to do with the driver.. it is straight into CPU, then either out to displays or down interconnector to driver board.

If this were me..  would be following the switch closures to the CPU and then to the first chip inline which im assuming would be some sort of buffer like a 7407. Any voltage spike to this chip would take it out... thats what its designed to do. Had the coil diode been put in the wrong way round.. i would be looking at this buffer chip... maybe coin door switches share same chip?

look at your schematics for GORGAR and see if the coin door test switch AND 3 drop switches are on the same female connector and also  a common IC

Boards tested fine on Williams board tester by Skybeau... we know that these are good then

OK a little progress. I hope.

Found a bad connection at the MPU board harness plug where the switches controlling the test switches go.
Once this was sorted, I am able to go into test mode and do the solenoid test. All work except 4 which is the GOR targets. my problem one.

So, test confirms solenoid does not fire when in test. (all others good in test).
Multimeter shows no earth on solenoid during test sequence.
Shorting transistor activates solenoid.

Looking at the inputs to the MPU board in the manual, there are special switch inputs, switch columns and switch but all are on the driver board only.

????

J.D.