Groups of segments are missing or locked on; for example segments h, j, k, m, n, p and r missing.

Missing or stuck segments from a bad SRC pack on the CPU board

Cause: A failed resistor/capacitor pack among SRC1-SRC9 on the CPU board; SRC5 for the h-r segment group.

Checks

• Remove the suspect pack and test it out of circuit; in circuit readings are meaningless.

Fix

• Replace with a bussed resistor network (1k or 4.7k x 9) with its common pin in board pin 1 and the ground pad left open, keeping C49-C56 fitted, or build an equivalent from discrete parts.

Systems

• Williams System 11
• Williams System 11A

Related tips

• Displays dead after the CPU board was removed
• System 9 versus System 11 display data
• What the SRC resistor/capacitor packs on the CPU board do
• SRC packs cannot be tested in circuit
• Lizard eye flashers locked on, then not flashing: bad drive parts and a missing resistor
• Whole groups of coils or all flashers dead: A/C select relay stuck
• Checking ground and +5 V on the CPU board
• Random slam tilts: replace the SRC6 resistor pack on the CPU board

Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Three, Clay Harrell