The test/ service switch is often a green or yellow button. You can usually only get to it from inside the cabinet. Follow the wires from r or 15 on the jamma connector. This should take you to the switch
http://www.jammaboards.com/jcenter_jamma_pinout.html
Check the wire for cuts or places where it could be shorted. At the button make sure the wires are connected to just the connectors and not touching anything else.
Make sure the black is on the common and the other is on the open. See picture
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Sounds like your switch is activating as soon as you get out of your boot sequence
Ok so this is my Cabinet; finally got on with an account and everything.
http://www.jammaboards.com/jcenter_jamma_pinout.html > According to this layout I followed the test and the service cables.
Service > not connected to anything at all, nice clean cut on the wire, looking like it was never connected to anything before.
Test > Was connected to switch but is now disconnected from it.
I pulled both wires out of zip-tided bundle and pulled them both all the way back to the JAMMA connection to make sure they don't cross anywhere or short anywhere else.
In theory the switch that it was connected to is just a momentary switch so by default it is open and when you move the switch it'll close momentarily. Thus being disconnected (open) should be the same as if normally connected to the switch and this should rule out the switch being faulty and staying closed inside or something.
I have unplugged all of the connectors basically in the whole cabinet including the buttons and reconnected them. Cleaned the contact area on the JAMMA Board. Moved wires around that were all crossed up through out the cabinet, moved the ground cable around untwisting it from the all of the wires inside, separating it off to the side away from all of the wires.
Any other suggestions would be grateful. As my buddy said early the guy had it plugged in his garage and was able to play it, he even had the back off at that time. We loaded it onto my trailer on it's back and took it home. And now it's stuck in this Operator Mode. I called the guy that I got it from and he said that he never seen that before but knew about the switch up in the front by the coin door area but that is all he knew about it. He did not build the cab, he had bought it off of someone else.