I just recently bought a Cavalier CS-80C machine and need a little help. Almost ever works fine except for some lights? There are three lights, two small 6 watt bulbs run two simple signs. One of these is working but the other is not? That it was simply the bulb but that is not the case. All wiring looks fine? The other is the fluorecent "Coke" sign. This too I thought was the bulb, but a new bulb will not light either? There is a black square plug that looks fine, but I'm wondering is something is wrong with it? Not sure how to tell? Can tips?