The game acts strangely now and then, slam-tilting or firing coils for no reason.

Hook: random slam tilts or coils kicking

Cause: A switch strobe wire grounding intermittently, usually the green wire with yellow trace at the left drop target bank pinched against the playfield support bracket.

Checks

• Inspect that wire where it passes the support bracket.

Fix

• Insulate it with tape or heat shrink and tie it clear of the bracket.

Systems

• Data East CPU Version 3

Games

• Hook

Related tips

• Hook: random slam tilts and coils kicking
• Hook: CPU and display EPROM types and latest versions
• Jurassic Park: coils fire at random, fuses blow, switch matrix shorts

Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)