The game occasionally slam-tilts or fires solenoids for no reason.

Hook: random slam tilts and coils kicking

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

Checks

• Inspect that wire where it passes the support bracket.

Fix

• Repair the insulation with tape or heat shrink and tie-wrap the wire clear of the bracket.

Systems

• Data East CPU Version 3

Games

• Hook

Related tips

• Hook: random slam tilts or coils kicking
• Hook: CPU and display EPROM types and latest versions
• Jurassic Park: random coils, blown fuses and switch shorts

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