The Kong punchback fires at random, and modes such as multiball start from the wrong shot (the gong shot, or the gong kickout) instead of the right orbit. Switch, coil and node board tests show nothing wrong.

Kong punchback fires on its own and multiball starts from the wrong shot: loose switch

Cause: The punchback's normally closed switch had worked loose and its blades no longer made firm contact, so vibration (the gong kickout shakes the game) opened it.

Checks

• In switch test, with the playfield down and the coin door interlock pulled out, tap the playfield and work the nearby kickout while watching the punchback switch.
• Wiggle the wires at the CN13 node board connector during switch test to look for related faults.

Fix

• Remove and retighten the switch, and bend the blades for firm contact.

Systems

• Spike 2

Games

• King Kong: Myth of Terror Island (Pro)

Related tips

• Lower pop bumper stops firing after nearby work: skirt pin off the spoon switch

Source: Pinball Repair help group!! (Facebook group)