The display +62 V supply measures above 70 V.

+62 V reads over 70 V

Cause: Someone changed the 1N4759 zener on the controller board to push more voltage into a worn-out display, common on games brought back from overseas.

Checks

• Check the zener at D3 (D2 on WPC-95) is a 1N4759 (62 V).

Fix

• Fit the correct 1N4759 zener and replace the outgassed display.

High voltage section: work with the game unplugged.

Systems

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

Related tips

• Outgassed displays and the 5 V supply
• Dot matrix display supply voltages
• +62 V collapses to about +12 V under load
• -125 V reads about -140 V
• -125 V and -113 V read the same and the display is dark
• Replace the whole display, not just the glass
• Negative HV low and display barely lights
• +5 V or +12 V missing at the display

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