Unplug all but J1 when using the test EPROM in the game

If you run the test EPROM with the CPU board still in the game, disconnect every connector except J1 first, or all the coils and lamps may turn on together.

Systems

• Bally 6803

Related tips

• Bench-test a CPU board with the 6803 test EPROM
• CPU jumpers JW1-JW6 for game EPROM size
• Test EPROM socket signals at U3
• Find a bad 6803 or a shorted bus line
• PIA outputs not toggling under the test EPROM
• Test EPROM memory test does not pass
• Electronic spares for 6803 board repair
• Cybernaut can have a -35, 6802 or 6803 boardset

Source: Repairing Bally 6803 Pinball Games from 1985 to 1989, Clay Harrell (pinrepair.com)