Every lamp in one row or column stays off.

An entire lamp row or column is out

Cause: If the wiring to the board checks good, the row or column driver on the driver board has failed.

Fix

• Repair the driver circuit for that row or column.

Systems

• Williams System 11
• Williams System 11A
• Williams System 11B
• Williams System 11C
• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• A lamp column or row stays on all the time
• Testing lamp-row drivers with a test lamp
• Testing lamp-column drivers with a test lamp
• Lamps light twice in the all-lamps sweep, or two lamps act as one
• A lamp row very bright or dead
• A row or column of lamps stuck on and too bright
• How the WPC lamp matrix works
• The three WPC lamp circuits

Source: Pinball Machines: How They Work & Troubleshooting, Norbert Snicer