Why the score motor home switch arcs on opening only

The score motor itself measures around 2 ohms, so when the home switch opens to stop it, the collapsing field produces a large arc. Closing the switch makes little or no spark. This is why the home switch and the flipper EOS switches are the two contacts most prone to burning.

Systems

• Electro-mechanical

Related tips

• Check the score motor switches before power-up
• What the score motor does
• Score motor switch numbering (Gottlieb and Bally)
• Score motor overruns or freezes: worn home switch
• Getting at score motor switches, and slowing a sequence down
• Finding a Gottlieb score motor switch from its schematic name
• Gottlieb score motor overshoots: brake switch
• Leave score motor switches alone unless clearly faulty

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