These are photos from an article I wrote for Gameroom Magazine that was published in March 1999. The article can be found at Prototype vs. Production.

Photo 1 - Right hand side of Spiral Loop, showing third (center or upper-right) magnet.
Photo 2 - Underside of playfield, showing third magnet.
Photo 3 - Underside of playfield, showing door lamp circuit board with Gum-Ball flash lamp board installed. Note connector for second flash lamp board, not installed.
Photo 4 - Closeup of flash lamp board, and playfield part drawing from game manual showing door lamp board with two flash lamp boards installed.
Photo 5 - Mini playfields. Production (left); prototype (right).
Photo 6 - Original left and right Spiral loop signs.
Photo 7 - Posts and rubbers installed in the jet bumper area.
Photo 8 - Dual optical switch circuit boards. Production games have a single, special circuit board.
Photo 9 - Clock face decals. Early production (left); late production (right).
Photo 10 - Platform leg leveler. Production game cabinets had the rear leg bolt holes moved so that the game could be made steep enough.
Photo 11 - Blue PowerBall™. Note how difficult it is to see on playfield.