Dot matrix HV parts grouped by supply

-125 V: Q6 (MJE15031), Q4 and Q5 (MPSD52), D4 and D5 (1N4758; D1 and D18 on WPC-95); these also feed the -113 V side, so replace those parts too. -113 V: Q7 (MJE15030) and D6 (1N4742; D3 on WPC-95), which sets the drop from -125 V. +62 V: Q3 (MJE15030; Q1 on WPC-95), Q2 and Q10 (MPSD02; Q2 and Q3 on WPC-95), D3 (1N4759; D2 on WPC-95). Replacing only one voltage's parts is possible but not recommended.

Systems

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

Related tips

• Dot matrix display supply voltages
• What the WPC dot matrix controller does
• Which dot matrix displays fit WPC games
• Rebuilding the dot matrix high voltage section
• Dot matrix display blank or faulty
• Dot matrix display power connector pinout and voltages
• One or two display columns stuck on
• Resets caused by a failing dot matrix display

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