The inline drop targets still score their points, but hitting the first target no longer lights the spinners, and completing the bank no longer lights the free ball (the standup gives a credit instead).

Drop targets score but no longer light features: cracked switch matrix connector

Cause: A cracked switch matrix connector at pin 8, the first drop target's switch line. The scoring still worked through the other targets, so the fault was easy to miss.

Checks

• In switch test, close each drop target switch one at a time and confirm the right switch number shows.
• Inspect the switch matrix connectors on the MPU for cracked housings and loose pins.

Fix

• Replace the cracked connector housing and repin it.

Systems

• Bally MPU AS-2518-35

Games

• Future Spa

Related tips

• Knocker fires instead of the outhole kicker: bad solenoid driver J4 connector
• MPU gives 3 flashes after reassembly: two 15-pin plugs swapped
• Three flashes and 8s or 9s in the hundreds digit
• Flickering displays and flipper drop-outs from a poor backbox ground
• 12 V at the rectifier board but not at the MPU
• Rectifier board J3 (to backbox boards) pins
• Seven flashes but no attract mode
• All score displays blank with the MPU fully booting

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