This era of Bally doesn't have any direct cabinet switches (except the test switch) - seems they are all a part of two switch matrix's.

You probably need to start confirming all the switch lines are working correctly, my bet will be a faulty diode somewhere in the switch matrix?

You could track down one of the coin wires and connect it directly to the cabinet strobes - IE briefly connect pin 2 or 3 of J3 to pin 9, 10 or 11 of J3 and see if you get a credit? If you do the board is working and you have a cabinet or door wiring issue - if still no credit you have a board problem.

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