A segment is missing after the 4050s and UDN chips seem fine.

Check the segment resistors before buying a UDN7180

Cause: A bad resistor, or a bad solder joint on one, after the UDN7180 output.

Checks

• Find the missing segment on the schematic and follow it through its UDN7180 to its resistor.
• Measure the resistor: it should be within 10 percent of its marked value. Without schematics, measure them all; the 1/2 W ones are the usual culprits.

Fix

• Replace or resolder the resistor.

Systems

• Data East CPU Version 1/2
• Data East CPU Version 3

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