Test every fuse properly before first power-on

Steps

• Switch the game off.
• Pull each fuse from its holder (at least one end out); a tired fuse often falls apart as it comes out.
• Set the meter to continuity or lowest ohms; a good fuse reads 0 ohms (beeps).
• Check each fuse's value and type against the manual: look for oversized fuses and fast-blow where slow-blow belongs.
• Check the holder clips for looseness or heat damage while the fuse is out.

Systems

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

Related tips

• Checking a fuse properly
• WPC power driver board fuses and what they feed
• WPC: fuse holder snaps off the power driver board: replace the clips properly
• Find what is blowing a fuse
• WPC-95 line fuse
• Common fuse ratings to stock
• WPC-89/WPC-S driver board fuse ratings
• Fliptronics board fuses F901 to F904

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