- Main CPU: Motorola 6809 at 2 MHz, 8KB of RAM, and between 128KB and 1MB of EPROM for the game program.
- Sound CPU: Motorola 6809 (Pre-DCS), Analog Devices ADSP2105 (DCS)
- Sound chips (Pre-DCS): Yamaha YM2151, DAC, Harris HC55536 CVSD
- Operating system: APPLE OS (created by Williams, not related to the company Apple, but “Advanced Pinball Programming Logic Executive”)
There are six variations of the WPC hardware. The original version is sometimes referred to as WPC-89. The WPC MPU remained the same through all generation up to the addition of the security chip in WPC-S, and then the subsequent WPC-95 board. The variations are as follows:
- FunHouse – September 1990
- Harley-Davidson – February 1991
- The Machine: Bride of Pin·Bot – February 1991
Some Dr. Dude machines were also made using this WPC generation, although most were made using the later System 11 board.
- Gilligan’s Island – May 1991
- Terminator 2: Judgment Day – July 1991
- Hurricane – August 1991
- The Party Zone – August 1991
Terminator 2: Judgment Day was the first to be designed with a dot matrix display, but was released after Gilligan’s Island, due to Terminator 2 having a longer development time than Gilligan’s Island. Hot Shot Basketball) as well as in the first Shuffle Alley Game Strike Master Shuffle Alley – 1991.
Twilight Zone was designed to be the first pinball machine to use the new DCS system, but due to delays of the new hardware design it was decided to release it on the old hardware (using downsampled sound effects) instead. The redemption game Addams Family Values also used the DCS Sound System.