A bit more progress tonight. I got my good meter out and started measuring voltage around the score unit guaranteed step circuit. I will confess to not having a great understanding of AC. Most of my other stuff is DC and the AC ones I do have haven't needed any real work. Anyhow, I was able to determine I had 50V at the EB Trip relay 1 switch on both sides, indicating that the switch was passing it. I also had 50V on both sides of the Mixer 2 relay switch. Next in line is CU 7A. There I had nothing, on either blade. I say nothing but the meter said about 4 or 5 volts. Hmmm.
So I pulled the switch stack off the CU mounting bar, wrapped a wire tie around it to hold it together and took a look. Close-up, the points looked fine and everything seemed to be mating properly when closed. I decided to jump 50V direct to the switch and see what happened. I jumped from the output side of the Mixer 2 relay to the input side of the switch and then closed the switch by hand. All 3 score units stepped up! So now I know what the problem is. There is something wrong with the wiring going from the Mixer 2 relay switch to the CU 7A switch.
I got to thinking about how I could trace this out when I remembered I had found a cut wire up near the Position 29 relay. I had no idea what it was, nor any obvious sign of where it should go. Out of suspicion, I continuity checked it and found I had continuity to the 7A switch. Hmm, OK, what if I jump 50V to this wire from the Position 29 relay. Must have picked the wrong wire because I got a loud hum and switched it off quickly. So I voltage checked the broken wire - 50V.
Now I am confused - how can a wire which has continuity back to the 7A switch have 50V on it and not have that same voltage appear on 7A? I still have no answer for that one.
So I jump from my broken wire to 7A and toggle the stack by hand - score units step up again!
So, now I am in WTH is going on here territory? I know what the problem is, I can solve it by running a jumper to 7A from the mixer switch, which is the path drawn on the schematic. The problem is the wiring harness connections are essentially unknown. Why does a wire anywhere up near the Position 29 relay have any connection whatsoever to CU 7A? There is nothing up there that's in circuit for these guaranteed score steps. And that begs the question - what's the broken wire with 50V on it and where does it go? I see no sign of anything broken off the relays up there. I may just have to cut the harnesses apart and see what goes where but I'm not looking forward to those big black ones.
Here's the wire up near the Position 29 relay:
Mystery_Wire_(resized).JPG
And the 7A stack of out the lineup:
Cam7A_(resized).JPG
I've also decided the Score Extra Step relay switch was likely an operator hack. I thought it was broken but it looks like it's been cut:
Hack_(resized).JPG
And last but not least, the nice crispy Score Extra Step index coil:
Crispy_(resized).JPG