A crying shame to have to let go of such a rare machine.
You'd have to wonder what the original motivation was to manufacture a single player SS machine - the extra cost to make it multiplayer is negligible - anyone got any theories?
There's been a few stories, mostly the one on Clay's site
The reason for this was Ed Krynski (game designer) wanted to design one more classic single player card games before he retired. A call was made to the Gottlieb service department inquiring about the number of leftover System1 CPU board, and they made 211 games based on the 300 board available in the service department's stock.That story might not be true. I once found a link with a notable Gottlieb employee being interviewed which debunked the above story and noted it was just simply to get rid of the excess boards. I can't find the link though I know I have it somewhere.