Odd high scores usually mean a bad 5101 RAM

Audits and high scores live in a 5101 RAM at Z22, kept alive by a NiCad battery. This RAM fails often, and the built-in RAM check can pass a bad one, so strange high-score behaviour points to Z22. The red button (switch 25) at the top of the board only resets the high score.

Systems

• Gottlieb System 1

Related tips

• 5101 RAM at U8 fails often; speed matters
• Two flashes only: U8 5101 RAM
• Game keeps resetting: replace the 5101 RAM (an NVRAM works)
• Keep spare 6800, 6821 and 5101 chips
• Boots into audit mode every power-up with good batteries: bad 5101 RAM
• Locks up when a second game is started: bad 5101 RAM
• System 6 won't boot and fails the 5101 RAM test even after replacing it: bad 5101 stock
• Game always powers up in audit mode: bad 5101 memory chip

Source: Gottlieb System 1 Pinball Repair from 1977 to 1980, Clay Harrell (pinrepair.com)