Strange game behaviour or resets when certain playfield switches close.
Odd behaviour from a short in the tilt switch column
Cause: A short, bad diode or mis-wired switch in the matrix. Column 1 holds the tilt and slam tilt switches, so a short sharing their row or column causes odd results whenever other switches there close.
Checks
- Use the switch test to find switches that register wrongly.
- Inspect diodes and wiring in the affected row and column.
Fix
- Repair the shorted wiring or replace the bad switch diode.
Systems
Related tips
- Row or column fault on the playfield
- Switches stuck on: board or playfield?
- Switch test and audit display behaviour
- Board or playfield? The switch test jumper method
- Column 1 switches and switch wire colours
- Leon test: switch column drives (2J2)
- Switch matrix column test at 2J2 with Leon's code
- System 6: game stuck in tilt with switch 1 closed: cracked pins in the 2J2 plug
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)