Whenever You WORK on the pin: UNPLUG the Line-Cord ! Do not only toggle the Main-Power-Switch, do pull the Line-Cord. I want you to have a look at the fuses - they are neatly packed side by side - ONE fuse is for 110 VAC, I do not want YOU touching 110 VAC Power.
ipdb.org has a schema: http://www.ipdb.org/machine.cgi?id=438 - I must make a copy of the schema (down) onto my computer: "Right-Hand-side" Mouse-Click -> Save Target as ...
I read your description and I look at the schema. At schema-A-4 / B-4 I see TWO fuses (of 15 Amp). The first fuse then has Wire-Blue feeding playfield-lamps. This fuse is good. So the other fuse is in question.
I see (schema-B-2) the 8 Amp fuse for 110 VAC. At E-3 / -4, F-3 / -4 I see the 10 Amp fuse for the 50 VAC (Relays and Units). I do not see more fuses in the schema.
Unplug the Line-Cord. Look for the fuses. Can You find the 15 Amp fuses ? Take them out, have a close look at the fuse-holders - clean ? good (nothing broken) ? wires soldered-on ?
Put the "good" fuse (wire-Blue) into the socket of the other fuse. I cannot clearly see in the schema "what color": Is it "80" or "90" or "50" ? Well, on the other lug these fuse-holders have the same wire soldered-on ...
Plug-in the Line-Cord and start a game -> Do other lamps light-up ? If so: the "fuse in question" is shot -> get a new one.
If not (so): We must follow the wires -> check Switches on Game-Over-Relay.
Please report, Greetings Rolf