The #6 best selling Williams pinball game of all time is the Steve Richie F-14 Tomcat.
Even though they made 14,000+ of them almost no one has ever played the game as it was designed:
The clear coat was so thin on the game that it came with almost a full Mylar. I say "almost" because Williams left a 1/2" gap above the pop bumper (the most busy part of the game) and left the entire upper loop unprotected. F-14 was designed to be a super fast game, and all that lumpy Mylar slows it down.
Secondly, Williams used a million of the arrowhead inserts. These inserts pop up in every direction on many games (like MM), so why not populate an entire playfield with them?? Even when you heat them up and reseat them, they often pop up again a few weeks later. On most games the ball bounces around off the inserts like a golfball rolling down a cobble stone street.
Thirdly, many games shipped with the incorrect flipper coils installed.
Fourthly, the game's lights would short out against the targets, so Williams issued a service bulletin instructing operators to simply remove the lights and tie the remaining lights together to a single function. So the games have empty flasher domes that do nothing at all.
Fifthly, the single pop bumper gets an amazing amount of action and is usually completely worn through on most games.
So I had a few people bugging me over the years to restore their F-14. They are so much work that I kept putting it off until one day I had three to do at once.
Having three identical games to restore at once makes the restore work go much faster. You put the right size nut driver in the screwgun and go to town. You load up the HVLP and coat each game side by side. You print a bunch of decals and fix all the inserts at once.