Telling a -17 MPU from a -35 by connector J5

If the AS-2518 number is unreadable, count the J5 header pins including the missing key pin: 32 on a -17 board, 33 on a -35 or -133. The ROM jumpers differ, so know which one you have before changing them.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35

Related tips

• Telling a -133 MPU from a -35 or -17
• Tell a -35/-133 MPU from a -17 by counting J5 pins
• Testing an MPU in the game with only J4 connected
• MPU board test points
• MPU board test point voltages
• Why the MPU has ROM jumpers
• Converting a -133 MPU to a -35
• Setting up an MPU for the test EPROM

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