Coil command lines during test step 17

Nine coil lines run to the driver board through J4. In test step 17 each one goes from low to high to fire its coil; in attract mode all nine sit low. Coil outputs 3, 4 and 7 drive the optional coin counters and are skipped during the test, so do not expect them to fire.

Systems

• Gottlieb System 80
• Gottlieb System 80A

Related tips

• None of the CPU-controlled coils fire
• Some CPU-controlled coils are dead or locked on
• Where coil, sound and lamp commands come from
• Switch test (step 18) shows switches closed
• The battery-backed 5101 RAM uses only data lines DB0 to DB3
• Bookkeeping totals or score levels are wrong or missing
• What each System 80 board does
• Game check-out, part 2: what a healthy power-up looks like

Source: System 80 Service Manual, Gottlieb