Replacing the hard-to-find 48 V expander relay

The SEB (and flipper) relay is a 48 V type that is scarce. A Tyco/Potter & Brumfield KRPA-11DG-48 relay in a 27E122 eight-pin socket mounted under the playfield beside the SEB can be wired in instead; the guide shows the wiring in photos.

Systems

• Bally MPU AS-2518-35

Related tips

• Solenoid expander relay buzzes or does not switch
• How the solenoid expander board doubles up coils
• The bulb next to the solenoid expander board must work
• Centaur uses its solenoid expander for the ball-to-playfield kicker
• Expander games: check the controlled-lamp power first
• Expander game ejects or drops targets at the wrong time
• Drop target coils misfire after LEDs or a new lamp driver: expander boards need bulbs
• Drop target falls instead of the ball being kicked out (SEB games)

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Three, Clay Harrell (pinrepair.com)