The batteries also power the U9 ASIC clock

Besides U8, the batteries feed the 84-pin ASIC at U9, which keeps the time and date. Its battery pins are 1, 22, 43 and 64; under 4 V there points to a corroded PLCC socket, which leaking batteries damage easily.

Systems

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

Related tips

• Battery power not reaching the RAM: diode D2
• "Factory Settings Restored" every power-on
• Changing the CPU batteries without losing settings
• "Factory Settings Restored" at power-on
• "Factory Setting" or "Adjustment Failure" at power-on
• New batteries but still losing settings: test the holder
• Batteries die within days or weeks: diode D1
• New batteries die in weeks or settings still lost: U8 RAM

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