A coil locked on, and now connector 1J14 at the upper left of the CPU board is burnt.

Burnt coil connector after a locked-on driver

Cause: A shorted solenoid driver transistor drew enough current to overheat the connector.

Checks

• Inspect 1J14 for darkened pins or melted housing.
• Test the solenoid driver transistors.

Fix

• Replace the shorted transistor and repin or replace 1J14; replacing CPU power connector J1 is also worthwhile.

Systems

• Bally 6803

Related tips

• Lamp driver SCRs on the CPU board
• Fire a coil by grounding its driver tab
• Cut the original NiCad off the CPU board now
• What is on the 6803 CPU board
• CPU board test points
• Lamp driver SCR blew apart with a crack
• The 19 solenoid driver transistors
• Factory CPU jumpers by game

Source: Repairing Bally 6803 Pinball Games from 1985 to 1989, Clay Harrell (pinrepair.com)