Transformer secondary voltages and what they feed

The transformer gives 7.8 V AC (feature lamps), 12 V AC (logic supply), 7.3 V AC (GI, left as AC), 49 V AC (coils) and about 180 V AC (displays). All but the GI winding are rectified to DC on the rectifier board.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200

Related tips

• What each rectifier on the board feeds
• Rectifier board test point voltages
• First checks for any missing voltage
• A missing test point voltage: what to check first
• No voltage at any rectifier board test point: burnt mains wire to the transformer

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