I'm assuming this is happening on a Royal Guard?
If I remember correctly this era of game has a game over relay on the control bank in the cabinet. If your game has a game over relay, check the switches on that relay. One of them closes when the relay trips to supply power to the game over and match lights. This switch needs to be making good contact. Also check to be sure the wires at the switch lugs have not become detached.
If your game has a match feature control plug, check to be sure both pins on that plug are making a good connection with the socket.
If those are OK, the next thing to check are the lamps and lamp sockets. If you have a jumper wire you can jumper the GI power to each of the match lamp sockets to confirm that they will actually light. If they don't, then you'll need to replace lamps and/or clean sockets.
Once you know the lamps are good, if you still have the problem then you will need to look at the 0-9 stepper unit located in the upper-right area of the head. Check to make sure that all the rivets and wipers are clean and making good contact and that all the wires are soldered to the lugs around the outside of the bakelite disc. And, make sure that there are jumper wires soldered across all three sets of double-wipers.