How a hot hold relay coil destroys itself

A hold relay coil that runs hot burns the enamel off neighbouring turns. The shorted turns lower its resistance, which makes it hotter still, until it is brown and burnt. A hold coil reading lower than its twin elsewhere in the game should be replaced before it fails.

Systems

• Electro-mechanical

Related tips

• Momentary and hold relays, and the coil resistance a hold relay needs
• Relay banks and their reset coil
• Relay coil resistance and frame sizes
• Gottlieb relay coil equivalents and resistance
• Bally KKN relay coils and their C-7800 numbers
• Game resets but will not start: adjust hold relay and reset-completed relay latch
• AC and DC relays and coil stops are not interchangeable both ways
• Gottlieb hold relay runs the whole time the game is on

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