Use Leon's test EPROM, not the Williams one, for boot faults
The Williams test EPROM can simplify start-up checks, but its LED results are only valid once the board boots. For a board that will not boot, use Leon's test EPROM.
Systems
Related tips
- Leon's test EPROM: what to burn and where it goes
- Running Leon's test EPROM with the boards still in the game
- Leon's test EPROM fitted but the LEDs do not start flashing
- Leon code running but LEDs dark: bad CPU PIA IC18
- One EPROM instead of three
- Williams CPU boards only self-test when asked
- EPROM types used for System 3 to 7 game code
- Leon's memory test results (versions from 11/01/03)
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Two, Clay Harrell (pinrepair.com)