Fitting a CR2430 socket on the CPU board

Steps

• Remove the soldered original cell.
• Never solder directly to a lithium coin cell; it can explode.
• Solder the holder's positive leg into the board's + hole.
• Solder the negative leg to the wide ground trace below the battery position.
• Fit a CR2430 (3 V, about 270 mAh, 24 mm by 3 mm) and check about 3.2 V at U6 pin 2 (also pins 3 and 6; ground is pin 4). No external blocking diode is needed, as it is inside U6.
• The first power-up still shows the battery error; switch off and on again and it should boot.

Soldering to a lithium cell can make it explode.

Systems

• Gottlieb System 3

Related tips

• CPU battery and socket parts
• "Control board error, Low battery or Bad U3 or U6"
• Lithium battery leak damaging the CPU board
• Constant beeping, display blank, GI on
• Getting past the low battery message
• Using a remote two-AA battery pack
• Checking and setting +5 V at the CPU board
• CPU board 26285 versus 26285-1

Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)