you can remove the individual wire/pin connector where the burn mark is, clean it and reshape the connector, this should get you to where the game will come on and you can see what else is going on!. holding the connector and putting a flashlight on the backside of the connector (were the wires enter) you will be able to see how compressed that individual pin is compared to the others, cleaning with a pink eraser and reshaping typically will make the necessary connection. to remove the pin just insert a small item to push in the metal piece that holds the pin in place, once removed pry up that piece of metal so when you reinsert it into the connector it will hold the pin in place.
Is that Q-12 that you replaced? is so, and according to my schematics, Q-12 is used for payline number 4 bulb, which you wouldn't need. what changed when you had it replaced? my schematics are for a 10 MH board.
Jim