Quoted from pinball_ric:
The short has been present since before doing any work. Other than replacing the rectifier board. The original was bad. A lot of the light sockets were "fixed" someone soldering the bases. I assumed one of those was botched but they have all been replaced.
I will assume that who ever "fixed" the light sockets botched something that has not been located and fixed. A wire somewhere is not in the correct position.
Look for a red and white wire to have been replaced incorrectly. It is an easy mistake to make.
I hope what I have written below helps you out.
But get ready to do what you don't want to do. There is a Frye's Electronics in Austin not too far from you. You may as well go buy a sack of 1000 count 4" tie wraps and start digging into your wiring.
Quoted from pinball_ric:
Currently the wire on J1-8 is blue or violet. Hard to tell. This wire had burned up on the connector at least once before so this has probably been going on for awhile.
The J1-8 wire not being white sounds strange. I doubt that Stern ran out of white wire during assembly. So maybe somebody spliced in some bastard wiring---somewhere in your bundles of wiring. You will be able to tell very quickly by looking at the color of wire on ALL of your GI lights. Red and White are the blueprint colors for GI.
What I am saying above will be come apparent as you read below.
Good Luck. Wiring is a PIA; But I do like it.
I have six classic Sterns here. For the most part, the general drawings will cross across all MPU-200 Sterns. One of my Sterns has four wires of a different color than what is called for on the print. Another one has one wire that does not match what is on the print. At Stern, this shit happened.
This is the transformer/rectifier board drawing. J1 connector is in the middle of J-2and J3.
Pin 1 is Red wire.
Pin 2 is not used.
Pin 3 is a blue wire.
Pin 4 is your lockout key
Pin 5 is N.U.
Pin 6 is a Blue/White wire
Pin 7 is a blue wire
Pin 8 is a white wire
These drawings are oversized. You can click and enlarge.
The play field part of the drawing shows you that A2J1-1 is your return wire for GI (I spoke incorrectly earlier and quoted the Red wire as the power wire. Red is your return wire).
This pic shows the wires to match what is in the drawing.
Pin 1 = Red
Pin 2 = N.U.
Pin 3 = dark blue ( could possibly be a light blue ) This is a feature lamp bus. (see also Pin 7)
Pin 4 = Lockout Key
Pin 5 = N.U. (see also Pin 8 )
Pin 6 = Blue/White wire ( this Blu-W wire is the power wire for the flippers. You can trace it to the power lug of both flippers. Up between the flippers is a 1 amp slo-blo fuse. Pull that fuse and all of your solenoids go dead. However, the flippers are not fused and will continue to work with that fuse removed.
Pin 7 = Dark Blue ( see also Pin 3)
Pin 8 = White (reference the Play field drawing and it tells you that A2J1-8 is a 6 volt ac White wire).
Pin 1 Red wire: You will see that red wire spliced at every GI light at the base of the light.
Pin 8 White wire: You will also see this white wire on the power tab of every GI light. Pin 8 also meets up with Pin 5. This connection travels to test point 4 (TP-4) and then continues on to the F5 20 amp fused circuit on A2 rectifier board.
Pin 3 and Pin 7 come together in the circuitry of the rectifier board and hook up to bridge rectifier 1 (BR-1) Also, connector J3-Pin 6 is another dark blue wire that feeds the feature lights in the back box.
This is a feature light. It is hard to see due to my lighting but that blue wire at the base of the socket can be either from Pin 3 dark blue or Pin 7 dark blue. Look carefully and you will see some of the bare wire that has been soldered to the socket base and from here it will travel to another socket base and on and on until all of your feature lights are all hooked up to their common blue wire.
The blk/w wire I am pinching is the trigger wire for that feature light. (NOTE: These pics are from a Catacomb and are in no way representative of what you will see inside F2K).
EDIT: I want to add something with this pic of the GI circuit...
Consider the the Pin 8 white wire is the hot wire and red is return. If someone replaced some sockets and crossed the red and white wire, that white wire becomes a problem. It will be feeding power to the red side of the GI wiring and pushing current backwards into the system, which means it would be pushing backwards into Pin 1 Red wire.
I would do some isolation. First, remove the Pin 1 connector and kill your GI lights. Does the problem go away and you can now play a game? If that was no change, then remove the 2 dark blue wires for the feature lights. See if anything changes.