It's time to start answering some of these questions.
Quoted from Pecos:
Question 2: What do each of these switches on OXO's infamous 1000 Point Score Reel do?
Score Reel Switches CCC Label (resized).jpg
Switch 'A' is called the Zero Position Switch, AKA the Zero Break Switch, as Bally calls it. It opens when the Score Reel shows '0'. This switch is important when starting a new game because it 'tells the machine' when the Score Reel has been reset to zero.
Switch 'B', is also called a Zero Position Switch, AKA the Zero Break Switch. It is closed in positions 1-9. This switch, when closed, energizes the Score Reel Solenoid when the Reset Relay energizes. This allows the Score Reel to advance until it reaches '0' on the Score Reel and the switch opens. I guess you could also call it the Reset Switch.
Switch 'C' is the the 9th Position Switch, AKA the 9th Position Make Switch. It is open until '9' appears on the score reel. When '9' appears, this switch closes, completing the circuit to the solenoid on the Score Reel just to the left of the 1000 Point Score Reel, or the 10,000 Point Score Reel. Nothing happens until the 1000 Point Relay energizes again. Then the Score Reel moves from '9' to '0' and the solenoid on the 10,000 Point Score Reel energizes, incrementing the 10,000 Point Score Reel. The switch then opens and stays open until the 1000 Point Score Reel reaches nine again.
Quoted from pinballdaveh:
Question #2 I think the A switch is to pulse the score reel coil during reset.
The B switch is in parallel with all of the other score reel B switches in the reset relay hold in circuit.
The C switch is the 9th position carryover to advance the 10,000 score reel.
So, gang, how did pinballdaveh do? He did better than I did. I thought that I knew which switch did what, but I am more than a little bit embarrassed to admit that I did not. I learned a good lesson here!
Beware! It is important to note that early Gottlieb EMs work differently than this!
Now, for the next, obvious, questions. It is important to know the answers to these questions when debugging Score Reel problems!
What happens when:
Question 1: Switch 'A' is always open?
Question 2: Switch 'A' is always closed?
Question 3: Switch 'B' is always open?
Question 4: Switch 'B' is always closed?
Question 5: Switch 'C' is always open?
Question 6: Switch 'C' is always closed?