Zaccaria EM games are basically Williams under the skin . All the coils, steppers, score motor etc. are Williams. Coils are labelled Z instead of W, but apart from that, they are identical. I have owned and shopped quite a few of their games. If you search on IPDB, for Zaccaria EMs, you will see that the earlier games even had Williams logo aprons. The only difference in the late EMs was the sound. They stopped using the chime box and went to a electronic sound module with a speaker. That allowed them to have the Biri-Biri sound for scoring four million. instead of a replay, which was illegal in Italy. Even the module wiring diagram is on zaccariapinball. com nowadays. So you can make one if its missing, or add a chime box instead.
The play fields were bombproof, and are usually as new. The colors were very bright. Game design was good, even if some of the titles were a bit weird. Cabinets were the same build as Williams, coin doors identical apart from Z blanks instead of W. Moon flight and Supersonic ( Concorde themed) stand out as real well designed games, and Combat & Red Arrows if you like war themes.