https://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_80#Display_Problems
That is the "h" segment for P3/P4.
Group B "h" segment is controlled by Z16, pin 10.
Since the chip was socketed, prior rework is always suspect. Buzz for continuity. Perhaps replace Z16.
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Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact ... for board repairs
http://www.PinWiki.com - The Place to go for Pinball Repair Info