Quick checks on the similar System 1 power supply
The System 1 supply is close to the System 80 design. Q1 must be insulated from the back plate by its mica pad. +5 V reading about 2.4 V points to a bad Q1. With no +5 V and Q1 removed, IC1 pin 7 should read 14 to 15 V; if not, IC1 is bad. If Q1 runs very hot with no +5 V, SCR101 is bad.
Systems
Related tips
- System 1 power supply outputs
- Replacing power supply filter capacitor C1
- Acceptable System 1 supply readings
- Getting to the power supply solder side
- Power supply bring-up, step 1: inputs
- Power supply output connector pins
- Display high-voltage section of the power supply
- Logic and display reference section of the power supply
Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)