Permanently close the slam circuit on the CPU board

Steps

• This applies to games before Big House only.
• On the CPU board's component side, find the two neighbouring traces just right of Z26, scrape the mask and bridge them with wire and solder.
• Cut the slam switch wire right at CPU connector A1-J5 pin 10 (white with purple and black stripes; match it to a wire on the door's slam switch).
• Label the cut wire so an unmodified CPU board is never fitted without reconnecting it.

The coin door carries about 25 V for the lockout coil; if that touches the slam wire it can destroy the CPU board, which is why the wire is cut.

Systems

• Gottlieb System 80
• Gottlieb System 80A
• Gottlieb System 80B

Related tips

• Game won't start or boot because the slam circuit is open
• System 80 switch matrix diodes
• Testing the switch matrix inputs with the test EPROM
• Use exact chip types in the CPU clock circuit
• Which System 80 CPU board goes with which games
• Replace the decoupling capacitors on the CPU and driver boards
• System 80 CPU board connectors and what they carry
• Which CPU connector housings can be reused

Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)