Xenon keeps putting two balls in play after the battery died

Steps

• Replace the MPU battery.
• With the game off, take the 5101 RAM out of its socket.
• Put both balls in the outhole.
• Refit the 5101 and power on; the ball tracking should now be correct.

Systems

• Bally MPU AS-2518-35

Games

• Xenon

Related tips

• Lost World ROM set numbers
• All 7-digit displays show a dim first digit and comma
• Player 1 display shows credits and ball in play
• Repairing battery corrosion on the MPU
• Fitting a remote AA battery pack
• Game only makes chime sounds after a battery or RAM change
• Cut the original MPU battery off right away
• Bally-35 MPU: remove the on-board rechargeable battery before it leaks

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