Check the wire from the coil to its driver transistor
Steps
- Find the transistor for the device from the manual, or find the coil's ground wire colour among the plugs along the driver board's left side and buzz from that pin to the tabs of the left-side TIP transistors.
- With the game in attract mode, clip a lead to ground in the backbox and briefly touch the other end to that transistor's metal tab.
- If the device fires, the wiring is good and the fault is on the driver board.
- If not, look for a cracked header pin solder joint on the driver board connector or a broken wire; for a flashlamp, check its resistors under the playfield.
Systems
Related tips
- A cracked coil diode keeps killing its driver transistor
- Coil outputs available on System 3-7
- The coin lockout coil is meant to be on
- Solenoid driver test at 2J9 and 2J11 with Leon's code
- A low resistance coil points to a bad driver transistor
- Pop bumper or slingshot locked on
- Driver board transistors and what they drive
- Special solenoid trigger test at 2J12/2J13
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)