You are correct, this is the lock-in switch for the 10-point relay. The four EOS switches, which are all normally closed, are located on the four 10-point score units (one EOS switch per score unit). When any of the 10-point score units indexes, its EOS switch will be pushed open, allowing the 10-point relay to release.

Since none of your 10 point score units are indexing, none of the EOS switches ever open, so the 10-point relay stays locked on forever once it is energized. Bending the lock-in switch on the relay so it never closes "fixes" this infinite lock-on problem, but it doesn't get the 10-point score units working.

In the head of your game, there is a player-up stepper unit. This stepper is fairly easy to identify because it has a bunch of wires attached to the many wiper fingers that are on the stepper. These wiper finger wires are routed back to the stepper disc inside a spring, which protects the wiring.

The player-up stepper only has four positions. Each position selects which score units will receive the scoring from the playfield. When the stepper is reset, player 1 is selected. Step it up once, and player 2 is selected. Step it up once more, and player 3 is selected. Step it up one more time, and player 4 is selected. After that, the stepper won't advance any more.

The wiper fingers contact a different set of rivets on the stepper disc at each position, and it is this connection that determines which set of score units will receive the scoring. So if none of the 10 point score units work, I would suspect there is some failure with the 10-point wiper finger connection to the rivets. Either the finger is bent and not touching any rivets, or there is a broken wire at one of the solder joints (either on the wiper finger or at the disc), or something like that. So I recommend you look at the player-up stepper in the head and see if you can find anything out of whack there.

- TimMe

Thanks for posting the pics. I have to say, looking at your first pic, that red wiper finger wire kind of looks like it's clipped right at the point where it's supposed to be soldered onto the tab of the finger. It might just look that way in the picture, but have you checked the red wire at that connection point and confirmed it's attached OK?

If it's not that, then it would probably still be a good exercise to use an ohm meter to confirm you've got good continuity for this circuit through the player-up unit. According to the schematic, when the player-up unit is reset (that is, on player one) you should have continuity from the blue-white wire on the 10-point relay switch to the red-black wire on the coil for the first player 10 point score unit. If you don't have continuity, then there is some break in the wiring that goes through the player-up unit.

If you do have continuity, then the problem is likely to be at the N.O. (normally open) switch on the 10-point relay that drives the 10 point score units. As mentioned above, one side of this switch has a blue-white wire. The other side goes to the main yellow return wire. Check that this switch is clean and is making good solid contact when the relay is actuated.

Also, sometimes these relay switches are attached to the main yellow return wire with a thin jumper wire. If that jumper wire has fractured, you'll get the problem you are seeing.

- TimMe

If you have continuity between the switch on the 10 point relay and the drive coil of the player 1 10-point score unit (yes that was exactly what I meant), then when that relay switch is closed, the coil should be energized.

So, is that switch on the 10 point relay clean and making good solid contact when the relay is pulled in? What happens if you jumper that switch?

The only other possible failure point would be the switch main yellow return wire or the score unit coil black return wire, which you can check with a volt meter. There should be 50 VAC between the yellow wire on the 10 point relay switch, and the black wire on the 10-point score unit.

Other than having four open 10-point score unit coils (very unlikely), there isn't anything else that can go wrong in this circuit.

- TimMe

Try jumpering the blue-white wire of the switch directly to the 10 point score unit coil (the non-black wire) and then close the switch. That should make the score unit coil fire.

If it does, then you have a break somewhere in the circuit that is going through the player-up unit.

If it doesn't, try jumpering the yellow wire directly to the 10 point score unit coil (the non-black wire). That should make the score unit coil fire. If it doesn't, you have a non-working score unit coil.

- TimMe

For whatever reason, I don't think you can trust the continuity checker, because it's saying the circuit is good, but obviously the power isn't getting through the player unit part of the circuit.

Instead, you can use your jumper wire as a probe to narrow down where the break is. Start by clipping one end of the jumper to the yellow wire. Touch the free end of the jumper to the red-black wire on the coil of the 1st player 10 point stepper unit. It should fire. Assuming it does fire, now you can use the free end of the jumper as a probe to check the rest of the circuit.

Next, determine which of the player-up unit wiper finger wires is attached to the blue-white wire coming from the 10 point relay switch. You should be able to do that by examining the solder lugs along the edge of the player-up unit circuit board, to see where the blue-white wire is soldered to one of the wiper finger wires. From your pics, it looks like it is the red wiper finger wire, but you'll want to double-check that.

I'll assume it's the red wiper finger wire for purposes of discussion. Make sure that the player-up unit is reset. Touch the free end of the jumper to the solder lug on the player-up circuit board where the blue-white wire is connected to the red wiper finger wire. If the score unit coil fires, there is a break in the blue-white wire between the 10 point relay and the player-up circuit board.

If the score unit coil doesn't fire, the problem is farther along in the circuit. Touch the free end of the jumper to the wiper finger attached to the red wire. If the coil fires, the red wiper finger wire on the player-up unit has a break, and will need to be replaced. If the coil doesn't fire, the problem is farther along. Touch the free end of the jumper to the pad on the circuit board that the wiper finger is touching. If the coil fires, the contact between the finger and the pad on the circuit board is failing. If it doesn't fire, the problem is farther along in the circuit.

In this way, you can continue to work your way along the circuit, toward the coil, until you get to a point in the circuit where the coil fires. Then you will know that the section of the circuit between where the coil fires and the most recent point where it didn't fire will be where your wiring break is.

- TimMe

Great! If it's the red wire that has the break, you won't need to unravel any wiring harnesses, because that wire begins and ends on the player-up unit.

The only other tip I would give is that, regardless of the reason, you always want to avoid cutting the lacing, or otherwise trying to unravel, any wire harness on a pingame. That will just create a big mess, and you'll be sorry that you did it.

You can replace a bad wire in a harness without un-lacing it. There are a few different ways to do this, but the easiest way is to just run a new replacement wire along the side of the harness, and secure it to the harness with a cable tie every 12 inches or so.

- TimMe

Fair enough, but I'm not sure I follow the the results of your detective work, so let me ask a couple of questions -

1. What point EXACTLY did you touch with the free end of the jumper that made the coil energize?
2. What point EXACTLY did you touch with the free end of the jumper that the coil didn't energize?

As for the chime, don't worry about it, it's not going to sound while you are doing this kind of testing.

- TimMe

Yes, that's a good guess, now I understand what you were saying before. I think you've figured it out, and here are some simple steps to help you confirm your diagnosis:

1. Make sure that the switch on the 10-point relay (the one with the blue-white wire) is adjusted so that it closes properly when the 10-point relay is energized.

2. Use your jumper to connect these two points:
- Where the blue-white wire is attached to the switch on the 10-point relay.
- Where the blue-white wire is attached to the player-up unit.

3. Push the 10-point relay closed.

4. If the 10-point score unit advances correctly now, replace your temporary jumper with a permanent wire.

- TimMe

Great, glad you found it! No worries on the time it took to track this down, the important thing is that you got to the root cause so you can get your game working again.

- Tim