After a restoration with new power, MPU and driver boards, the drop target bank never resets, the right outhole kicker does not fire and a few MPU-controlled lamps stay dark. The coils fire if the driver transistor tab is grounded by hand, and none of them work in the coil or lamp tests, although the switch test is fine.

Target bank, outhole kicker and some lamps dead after board swap: miswired new cable

Cause: The newly bought interface cable between the MPU and the driver board was made wrong: some conductors had no continuity and two went to the wrong pins. The boards themselves were fine.

Checks

• If a coil fires when its driver transistor is grounded but not in the coil test, the driver output is not getting its signal from the MPU.
• Ohm out the MPU-to-driver cable pin by pin against the schematic, even when it is brand new.
• Confirm the MPU game setting matches the game.

Fix

• Replace or rebuild the MPU-to-driver cable so every conductor goes pin 1 to pin 1, and re-test coils and lamps.

Systems

• Gottlieb System 1

Games

• Cleopatra

Related tips

• Rebound, rollover, outhole and drop target switches dead: corroded J6/J7 switch plugs

Source: Pinball Repair help group!! (Facebook group)