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Quoted from pinzrfun:it stays LO then the PULSE light comes on when the sound changes/bulb lights up
This is the correct indication. See @terryb's 5th post in this thread.
In this application, the 4514 pins are mostly low except for a very brief high pulse on outputs enabling a SCR to illuminate its respective lamps.
Quoted from pinzrfun:how often do you use a truth table to determine what an output should be? Is it considering "cheating" as opposed to deciphering a circuit to figure it out? Or when it comes to these Bally/Williams games, do you have these various chips memorized by now?
I use datasheets all the time and often look at truth tables, I even download datasheets for the same logic chip from multiple manufacturers to find the best explanations. The 4514 is a good example, the Philips version datasheet has the best description of how the 4514 works in relation to how Bally uses it - actually in this specific case all the truth tables don't quite give you the full picture because they don't represent the effect the "EL" input has. I tried to expand it below to make it a little more clear in Ballys demultiplexer mode, it's not perfect but anyway.
Schematics don't always tell you how logic chips function. Besides basic gates you're sometimes better off looking them up.
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