DC supplies from the transformer panel

Three bridge rectifiers make the DC: about 12 V with a 10,000 uF cap (becomes the regulated +5 V, and also feeds optos), 20 V with a 33,000 uF cap (flashers, relays, lamp matrix, display controller) and 48 V with no filter cap (solenoids).

Systems

• Gottlieb System 3

Related tips

• A12 transformer panel fuses F3 to F7
• A12 transformer panel fuses F8 to F11
• Which bridge rectifier is which
• Boots to game over, then lamps and switches are dead
• Game won't boot: failed vertical fuse holder
• Erratic faults from a poor ground at the A18 board
• Playfield GI out
• Backbox GI out

Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)