The game reports a U6 checksum error.

"U6 Checksum Error"

Cause: The game ROM at U6 is faulty or badly seated.

Checks

• Check U6 for bent or folded pins.
• Check its socket for cold solder joints.

Fix

• Reseat U6, reflow the socket, or replace the ROM with a fresh copy for this game.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• "Checksum Error" at power-on
• G10 error with serial number all zeros
• 'Check F114 and F115' then ground short row 1: failed 12 V regulator on CPU
• Outhole, shooter diverter and gumball motor all dead: CPU board chip at U4
• Settings are lost at power-off even with fresh batteries: bad battery diode D2
• What is on the WPC CPU board
• Bench-check the WPC CPU switch matrix circuit
• Which System 11 CPU boards fit which games

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part One, Clay Harrell (pinrepair.com)