Adding backup jumpers to a WPC or WPC-S driver board

Steps

• On the solder side, mark each bridge's "+" lead (the offset leg), its "-" lead (diagonal to "+") and the AC leads, plus each capacitor's "+" lead (usually the top one).
• Buzz out every planned path with the meter before soldering; a wrong jumper can do serious damage. Use 18 gauge wire, board solder side up with J104 at the top.
• BR2 to C5 (most important): "+" to "+" and "-" to "-".
• BR1: one jumper from its AC lead (just below "+") to J101 pin 7. Join the "+" leads of C6 and C7, and add a jumper from C6 "+" to TP8.
• BR3: lower AC lead (below "+") to J104 pin 1; upper AC lead (left of "+") to J104 pin 2; "+" lead to the wide solenoid fuse trace roughly 2" under the bridge.
• BR4: "-" to C11 "-"; AC lead above "-" to J102 pin 1; the other AC lead (below "+") to J104 pin 4.
• BR5 to C30 (second most important): "+" to "+" and "-" to "-".

Systems

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

Related tips

• WPC-89/WPC-S driver board LEDs and test points
• Voltages made by the WPC power driver board
• Bridge rectifiers to use on WPC-S and earlier driver boards
• Supplies made on the WPC power driver board
• Bridge positions on WPC-S and earlier driver boards
• WPC power driver bridge rectifiers and +5 V regulator
• Driver board LED4 off and the game won't boot (WPC-S and earlier)
• Driver board LED5 off: flasher 20 V missing (WPC-S and earlier)

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