Narrow down a bad switch with a jumper lead

Steps

• With the schematic, list the switches in the path to the coil that won't fire.
• Clip a jumper lead across all of them from the farthest switch up to the coil.
• If the coil now works, the fault is within the jumpered part; move the far end of the jumper one switch nearer the coil.
• Repeat until the coil stops working: the switch just uncovered is the bad one.

Systems

• Electro-mechanical

Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part Two, Clay Harrell (pinrepair.com)