Manual reset: jumper TP5 to U9 pin 40

When the reset section is dead, the CPU can still be started for testing by jumpering +5 V at TP5 to U9 pin 40 with the board powered. If that does not wake it, try another 6800.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200

Related tips

• Testing the MPU reset circuit at U9 pin 40
• Quick test of reset transistor Q1
• Single reset parts that hold the LED on
• DS1811 reset chip: which version to use
• Replacing the MPU reset section with a DS1811
• MPU U9 voltages that show a working reset section
• Resets from a bad MPU J4 power connector
• MPU boots only when U9 pins 39 and 40 are shorted

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Two, Clay Harrell (pinrepair.com)