Do not confuse the E13 and E15 pads with nearby vias

Near the lower right corner of the U2 socket, two plain vias sit closer to the E13 and E15 labels than the real jumper pads do. The pads are slightly larger; the vias have nothing to do with the jumpers.

Systems

• Bally MPU AS-2518-35

Related tips

• MPU board test point voltages
• MPU stops before the 7th LED flash (no 43 V)
• Add a ground jumper on every -17/-35 MPU
• Testing an MPU in the game with only J4 connected
• Using a PC power supply as an MPU bench supply: which wires
• Turning on an ATX PC supply without a motherboard
• Where to clip a bench supply onto the MPU
• Bench-testing a -133 MPU: swap the R113 diode for a resistor

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