I've had this Pro Football in my possession for some time, it came out of someone's crusty old garage on the island here. It's always had issues, but I've worked through most of them except this one that I just can't resolve.
When starting a new game, the AB relay does not activate to reset the score reels.
From the startup sequence:
The following sequence takes place thru the closed switches on "S" relay:
a. The motor starts running
b. The total play meter and AB relay coil are actuated by switches on motor 3C and motor 1A
c. The reset "Ball Count" unit coil is energized returning the unit to zero.
d. The advance unit ("I" relay) is pulsed by motor 1A to its zero position
- The total play meter IS incrementing, and following the schematic, both the AB relay and total play meter go through the same set of switches (1A > 3C > S). I've also checked and adjusted all of those, so I don't think they are the culprit
- I suspected bad coils, so I replaced both the AB and AB Reset coils with the matching NOS coils ordered from Johns Jukes. This had no effect
- This isn't a 100% of the time issue. Maybe 1-in-10 or 1-in-20 times the AB DOES activate and the game begins as it should
- Unrelated (but possibly related), manually activating the relay resets the scores properly, but the AB Reset Relay fails to activate as well and must be manually triggered.
I've attached the relevant section of schematic and instructions, plus a picture of the AB coils (AB Reset is on the left, AB is on the right).
Any insights or ideas are welcomed, thanks in advance!