Replacing BR1 and BR2 on their shared heat sink

Steps

• BR1 and BR2 share one large heat sink, so if one has failed from heat replace both.
• Desolder both bridges from the driver board and unscrew the heat sink from each.
• Screw the new bridges onto the heat sink first, with a thin coat of white heat-sink compound across the top of each bridge.
• Fit the bridge-and-heat-sink assembly to the board and solder all eight legs.
• Do not cut the heat sink in half: a half sink levers on four solder joints and vibration can work the bridge loose from the board.

Systems

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

Related tips

• Load-testing BR2 in the game with a 6 A diode
• Won't start after a power surge, 5 V reads very low: failed C4 on the power driver board
• Row 1 short error and F114 blows at once: fault in the 18 V lamp supply
• Every opto dead and the opto board LED off: failed bridge BR5 for the unregulated 12 V
• 12 V and 50 V supplies read far too high: transformer line-voltage jumpers set wrong
• 'Check F114 and F115' with switch 24 open: missing 12 V, bad bridge BR5
• Voltages made by the WPC power driver board
• WPC power driver bridge rectifiers and +5 V regulator

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