Ive had 5 Zac games over the years and this is the only one with a missing or broken backglass.
The folding down header with a glass installed is the biggest killer i reckon, i also think that people tend to look after say a Gottlieb, Bally etc game more... its just a Zac... or its just a Playmatic etc.. but a Centaur is special and so extra care taken.
Last week i got told of one dealer that scrapped several zaccaria games simply due to missing backglass or non working neon... couldnt be arsed to repair.. game is a cheap Euro import so who gives a stuff?
If it aint Gottlieb, Williams, Bally its just rubbish.
LOL- thats my theory anyway