Taking the power driver board out of the backbox

Steps

• Turn the game off.
• Write a label on the side of every connector with a marker as you unplug it; several plugs share the same keying and can be swapped by mistake.
• Loosen, but do not remove, the Phillips screws holding the board; the mounting holes are slotted.
• Lift the board up and out of the backbox.

Systems

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

Related tips

• Learn the power driver board layout first
• WPC power driver board versions and where they fit
• Testing a coil diode on the driver board
• 20-second test for shorted coil driver transistors
• Testing a 74LS374 driver latch with the diode setting
• Replace the pre-driver along with a failed driver transistor
• Coil locks on as soon as the coin door closes: transistor shorted by the old coil
• Where the WPC coil and lamp drivers sit

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