A switch works intermittently even though the blades touch.
Switch contact point loose or missing
Cause: The contact rivet in a blade is loose (it wiggles or spins) or has fallen out.
Checks
- Try to wiggle each contact point with a fingernail.
Fix
- Replace the blade or the whole switch.
- Or flow a drop of solder onto the back of the contact where it meets the blade.
Systems
- Williams System 3
- Williams System 4
- Williams System 6 / 6A
- Williams System 7
- Williams System 9
- Williams System 11
- Williams System 11A
- Williams System 11B
- Williams System 11C
- WPC Alpha-Numeric
- WPC Dot Matrix
- WPC Fliptronics
- WPC DCS
- WPC-Security (WPC-S)
- WPC-95
- Bally MPU AS-2518-17
- Bally MPU AS-2518-35
- Stern MPU-100
- Stern MPU-200
- Bally 6803
- Gottlieb System 1
- Gottlieb System 80
- Gottlieb System 80A
- Gottlieb System 80B
- Gottlieb System 3
- Data East CPU Version 1/2
- Data East CPU Version 3
- Data East/Sega CPU Version 3b
- Capcom
- Electro-mechanical
Related tips
Source: Pinball Machine Care & Maintenance, Bernard B. Kamoroff (Bell Springs Pinball Alley)