The YP as descibed fires when 2-9 are made, a daisy chain set of contacts thru the 8 relays will activate that. So it sounds like a short somewhere tripping the YP relay. Check around jones plugs and harness coming off of control bank. I had a sharp lead off of a solder lug pierce a conductor and the game would go into gameover when a feature was made...
As to the tilt, slam switches etc