Bench-check the WPC CPU switch matrix circuit

Steps

• Enter the switch levels test.
• Unplug J212, J206, J207, J208 and J209 from the CPU board. All switches should now read open; if any show closed, the CPU board is faulty.
• Rows: clip one end of a lead to J207 pin 1 and touch the other to J209 pins 1 to 9 in turn. The display should show switches 11 through 18.
• Columns: hold one end on J209 pin 1 and touch J207 pins 1 to 9 in turn. Expect 11, 21, 31 and so on up to 81.
• Any missing number means the CPU board is faulty. Some games do not use columns 7 and 8, so missing 71 and 81 is normal there; check the switch matrix table.

Systems

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

Related tips

• Running a WPC CPU board on the bench
• What is on the WPC CPU board
• Country DIP switch settings on WPC-S and WPC-95 CPU boards
• What fails on a WPC CPU board
• WPC CPU board versions and where they fit
• WPC-S and WPC-95 CPU boards need the matching security PIC
• Pre-WPC-S CPU EPROM size jumpers W1 and W2
• Country jumpers W13 to W18 on pre-WPC-S CPU boards

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