put paperwork for the 831-ZE and 831-ZP on
http://bingo.cdyn.com/slots/except for the schematic, the diagrams are the same for both games, so the files are mostly in the 831-ZE folder.
a major difference between the two games is the ZE ... at least on this schem ... uses the new style hopper while the ZP uses the old.
oddly, the ZE schem is w-1046-1808 while the ZP is w-1046-1017. In addition, the ZP schem says "831 ZE" on it. Oh well.
the top row of lugs on reel 1 wiper contact plate diagram labeled "ext" go to the payout counter disc. Those traces aren't used on your game and looks like the refurb company didn't bother running the wires.
as you can tell from notes on the diagram, the same drawings were used for many games. In this case, I have two different versions of the w-1041-1939-1941 diagram. When they redrew it, the left off one note and added another.