Reset is good but the CPU still does not run.

Check the 6803 clock at U1 pins 2 and 3

Cause: Clock circuit fault (rare): the 3.58 MHz crystal or C2/C3 (27 pF), less often C4/C5 (.1 and 4.7 mfd).

Checks

• With a logic probe both U1 pins 2 and 3 should pulse; a meter reads about 1 V at pin 3.
• Cycle the power after probing, since touching the clock pins can stall the CPU.

Fix

• Replace the crystal or the 27 pF caps if the clock is dead.

Systems

• Bally 6803

Related tips

• What is on the 6803 CPU board
• Bench-test a CPU board with the 6803 test EPROM
• Power a 6803 CPU board on the bench with a PC supply
• CPU board test points
• Factory CPU jumpers by game
• Interrupt circuit failure from the 2x12 VAC signal
• 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)