System 80 switch matrix diodes
Every matrix switch has a diode to its strobe line, band toward the strobe. The original part is a 1N270 germanium diode (NTE109); a 1N4004 works as a replacement. Strobes pass through buffer chips Z11 and Z12 and returns through Z13 and Z14 on their way to RIOT U4.
Systems
Related tips
- Fit a remote AA battery pack to a System 80 CPU board
- Pop bumpers fire but don't score: bad switch diode on the diode board
- Testing a switch diode out of circuit
- Lane change from the flipper button does nothing: bad 1N270 diode
- Spare diodes for coils and switches
- Switch diode failures and what they look like
- Testing a leaf switch diode in place
- Test the switch column drivers with a diode jumper
Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part Two, Clay Harrell (pinrepair.com)