Never spray contact cleaner or WD-40 in an EM

Contact cleaner is made for 5 V gold and tin contacts and does nothing for the silver and tungsten contacts that switch coil power in an EM. Both it and WD-40 are highly flammable, and the arc at a switch can ignite them and set the cloth-covered wiring alight. Dirty switches are a mechanical job: file and adjust them.

Flammable sprays can be ignited by switch arcs and start a cabinet fire.

Systems

• Electro-mechanical

Related tips

• Do not use spray contact cleaner
• Cleaners for EM parts and cabinets
• Replacement switch contacts for EM games
• EM rotating contacts and score motor lubrication

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