System 7 SW1 diagnostic codes

With the coin door open, press SW1 once. "0" for a second then blank and back to attract: pass. 1: IC13 (2114) or IC20 ROM. 2: IC16 (2114). 3 or 4: IC17 ROM 2. 5: IC20 ROM 1, door closed or memory protect fault. 6: IC14 game ROM. 7: IC26 game ROM. 8 or 9: IC19 (5101), door closed or memory protect fault. Repeat several times and only trust consistent results.

Systems

• Williams System 7

Related tips

• EPROM types used for System 3 to 7 game code
• What System 7 codes often turn out to mean
• Flipper ROM color codes by system
• System 7 diagnostic display stays lit on a working game
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• System 7 CPU board test points
• Which System 3 to 7 games use which flipper ROM system
• A System 7 CPU board can run any System 3 to 7 game

Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Two, Clay Harrell (pinrepair.com)