I thought they were some real pinball machines with this setup too aren't there? Like to activate magna-ball or control a second set of flippers?
Yes, there are some tables with separately-controlled upper flippers (Family Guy has Stewie's mini-playfield, Nip-It has the "ballygator", etc.) and a few with MagnaSave. (Black Knight, etc.)
The good news is that no table uses upper flippers and MagnaSave so you can tie both encoder inputs to a single button using the "backwards wiring" shown in the first diagram below or the blocking diodes shown in the second.
Depending on the tables you want to play, you may want Ball Launch, R/L/U Nudge, and (if you
really want to go overboard) R/L Upper Flipper/MagnaSave.
- AFAIK the diagram below covers all possible pinball table buttons.
- Instead of standard microswitch buttons for the flippers/nudge, you might want GGG Class-X with True-Leaf Pro or Ultimarc Goldleaf buttons.
If you're using 2-terminal buttons (Goldleaf, leaf switches, etc.) you can use diodes like this to isolate the MAME switches from each other while allowing Upper Flipper/MagnaSave to apply ground to both inputs.
Scott