If it does it with another PCB. 100% you have a short or more likely break in your wireing. Somewhere.
Check the insulation where the wires touch the battlefield. And any stray wires not tied into the harness that might be broken internally if flexed or vibrated and can't be visibly seen. (Like stray ones in pic)
I had that on my shadow causing some battlefield targets to work intermittent
Check all the opto control boards and optos (every opto in the machine) one bad opto can mess the whole switch matrix. Don't forget the sanctum opto. Check for bad connections or solider blobs as well. Or cold solider joints.
Check the coindoor interface board for solider blobs or cold solider.
And if you haven't already. Visibly inspect the wires coming off the battlefield coil. And DMM test or replace the diode on it. And if it was done before, is it on the right direction?
It's not as hard as it seems. Just a little time and patience and you will sort it out.
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