Getting to the power supply solder side

To reach the solder side you must remove the four corner screws, the two heatsink screws for the edge TIP31s and the two Q1 screws, then desolder Q1, and solder it back to test. Many jobs, such as C1, can be done without this; a replacement power supply board is the other option.

Systems

• Gottlieb System 1

Related tips

• System 1 power supply outputs
• Replacing power supply filter capacitor C1
• Power supply bring-up, step 1: inputs
• Power supply output connector pins
• Quick checks on the similar System 1 power supply
• Display high-voltage section of the power supply
• Logic and display reference section of the power supply
• Power supply bring-up, step 2: CPU load

Source: Gottlieb System 1 Pinball Repair from 1977 to 1980, Clay Harrell (pinrepair.com)