Arcade machines, particularly classic models, represent significant investments for collectors and operators. Protecting these valuable pieces of gaming history from electrical damage is crucial for their longevity. Overvoltage events, whether from lightning strikes, power grid fluctuations, or internal component failures, can instantly destroy sensitive circuitry. Several protection methods have become standard in the arcade industry.

The most common overvoltage protection device found in arcade cabinets is the Metal Oxide Varistor (MOV). These components are typically installed across the AC power input lines. MOVs act as voltage-dependent resistors, normally presenting high resistance. When voltage exceeds a specific threshold—typically 130-140% of normal operating voltage—the MOV's resistance drops dramatically, creating a short circuit that shunts excess energy to ground and blows the main fuse or circuit breaker, safely disconnecting power.

Another prevalent method is the crowbar circuit. This protection scheme gets its name from its drastic action—like dropping a crowbar across power lines. It continuously monitors voltage and, upon detecting an overvoltage condition, triggers a thyristor to create a deliberate short circuit. This immediate action causes a fuse to blow or breaker to trip, protecting downstream components. Crowbar circuits are particularly effective against sustained overvoltages.

Many arcade machines utilize dedicated surge protection devices (SPDs) installed at the power entry point. These external or internal units often combine multiple technologies, including MOVs and gas discharge tubes, to handle different surge magnitudes. They provide the first line of defense against external power surges entering through the AC mains.

Additionally, modern arcade power supplies often incorporate built-in overvoltage protection (OVP) circuits. These electronic monitoring systems automatically shut down the power supply output when voltages exceed safe operating parameters, preventing damage to the logic boards, monitor, and other critical components.

For comprehensive protection, experts recommend a layered approach: using an external surge protector for the entire machine, ensuring properly rated internal fuses, verifying MOV functionality, and maintaining power supplies with working OVP circuits. This multi-tiered strategy provides the best defense against the various overvoltage threats that can permanently damage valuable arcade equipment.