Learn the power driver board layout first

Lay the board layout from the manual beside the real board and find the coil drivers, lamp row and column drivers, fuses and connectors. The connectors are numbered with pin 1 marked, and these are the connector and pin numbers the on-screen help messages refer to. For example coil 12 is driven by Q52.

Systems

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

Related tips

• Taking the power driver board out of the backbox
• 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
• Where the WPC coil and lamp drivers sit
• How a WPC coil, flasher or lamp driver chain works

Source: Pinball Machines: How They Work & Troubleshooting, Norbert Snicer