Quoted from MarkG:I believe it was to make the 0-9 unit harder to track and calculate the match at the end of the game. It was a way to better "randomize" the match. I think my Rack A Ball does the same thing.
/Mark
I stumbled across this last week, on Bank-A-Ball, while trying to fix the bell for 5 point scoring. Saw the difference between the point scoring and bell ringing on the schematic and with a test lamp. Turns out my issue was too much travel on the clapper - it rested on the bell when the coil was energized.
But... then I checked out a few other machines’ schematics around the BaB timeframe and found a suprising variety of techniques to do, what John Osborne calls, “Match Mixing”. Of the six machines I looked at, there were five different techniques used… from point filtering to injecting additional signals such as a pulse from the 50 point relay and from the game feature circuits. Some machines drive the 0-9 unit with the 10 point relay instead of the 1 point relay...
