A lamp problem traced to one socket; moving it may give a crackling sound.

Odd lamp faults from a conductive socket

Cause: Gottlieb used an organic flux that can conduct, so residue on a lamp socket can short.

Checks

• Wiggle suspect sockets and listen for crackling.
• Unsolder groups of bulbs to narrow down the faulty socket.

Fix

• Clean the flux off the socket joints or replace the socket.

Systems

• Gottlieb System 3

Related tips

• Lamp diodes sit on small boards at each socket

Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)