A coil fires repeatedly like a machine gun at a particular point, for example the knocker rattling off at 40,000 just before a 50,000 replay.

Find a chattering switch by watching for sparks in the dark

Cause: A switch in that circuit is gapped too close and oscillating.

Checks

• Run the game up to just before the fault with the playfield raised and the backbox open.
• Turn out the room lights and trigger the fault by hand; the faulty switch shows as a stream of blue sparks.

Fix

• Re-gap that switch.

The game is powered with the backbox open; keep hands clear of line-voltage parts.

Systems

• Electro-mechanical

Games

• Spanish Eyes

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