Browned pins at driver J3, with resets or a dead game.

Burnt pins at solenoid driver J3

Cause: J3 pins 10-12 (orange, supply) and 13-17 (white/brown, ground) carry heavy current and overheat; pin 12 is the usual one.

Checks

• Inspect the header and housing at those pins.

Fix

• Replace both header and housing pins; replace an IDC housing entirely with a 25 pin .100" crimp housing.
• Add the ground and TP1-TP3 jumpers.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200

Related tips

• Rectifier board J3 (to backbox boards) pins
• Solenoid driver TP5 under 13 V
• Burnt rectifier J3 pins 8 and 17
• 12 V at the rectifier board but not at the MPU
• Solenoid driver board J3 pin functions
• Solenoid driver/regulator board test point voltages
• Ground mod for the solenoid return at J3 pins 23-24
• Jumper TP1 to TP3 on the solenoid driver

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)