Bottom cabinet relays and their drivers

Relays in the lower cabinet run on 20 V. Q (game over) is Sol.31 on driver MosFET Q32; T (tilt) is Sol.30 on Q31; A (backbox GI) is Sol.25 on Q26. Every game has Q and T and nearly all have A.

Systems

• Gottlieb System 3

Related tips

• What the A3 driver board drives
• Spare MosFETs for the driver boards
• Only logic-level (L) MosFETs work on the driver board
• Proving the driver board's switch strobes
• Logic chips worth stocking
• A2 and A3 plug wire colours
• Coil or flasher on as soon as the game powers up
• Testing a dead coil or flasher

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