The game resets in the middle of play.

Game resets during play from a failing logic filter capacitor

Cause: The orange 12 V filter capacitor on the bottom panel, which smooths the supply for +5 V logic, has dried out.

Checks

• With the game on and the meter on AC volts, measure across the capacitor; after the reading settles, more than about 0.2 V AC means it is bad.

Fix

• Replace it with a 105 degree computer-grade capacitor of 6,800 to 15,000 mfd at 16 V or more; 10,000 mfd is ideal.
• Fit the new one with correct polarity.

The bottom panel carries 120 V AC from the wall; unplug the game before touching the line filter, fuse block or transformers.

Systems

• Gottlieb System 80
• Gottlieb System 80A

Related tips

• First power-up, step 1: check the bottom-panel fuses
• System 80 games have no surge protection on the line input
• What the two System 80 transformers supply
• Bottom-panel bridge rectifiers and fuses
• Quick diode test of a bottom-panel bridge rectifier
• Identifying the leads of a bottom-panel bridge rectifier
• A bottom-panel fuse blows the moment the game is switched on
• What the System 80 reset (watchdog) board does

Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)