Whole vertical or horizontal lines missing from the display.

Missing rows or columns on a pin-style display

Cause: On pin-style glasses the right-angle pins break off at the edge of the glass from vibration. Later displays use a flat ribbon joint instead.

Checks

• Inspect the pins along the glass edge.

Fix

• Re-attach broken pins with conductive silver epoxy. This rarely works if more than two horizontal or two vertical pins are broken; otherwise replace the display.

Systems

• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• Repairing a missing display line with conductive epoxy
• Replace the whole display, not just the glass
• Dot matrix display faults
• +5 V or +12 V missing at the display
• DMD line out from a broken pin at the glass: bridge it with conductive glue
• One or two display columns stuck on
• Random display lines and all flippers energising at power-on
• Blank display, garbage or diagonal lines: reseat ribbon cables

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Three, Clay Harrell (pinrepair.com)