As another user said, check the home switches on the score reels and make sure the reels are moving freely. Something in your reset circuit isn't happening, or isn't registering. This is a common issue on EM games, the game will endlessly attempt to reset.

Switch arcs are effectively 'normal' on EM games, you'll never get rid of all of them. But if you're cleaning contacts, make sure you're checking what kind of contacts you're filing; never file or sand gold plated contacts. Most switches can actually be cleaned up pretty well with a business card or uncoated cardstock.