The game boots, displays work and a game starts, but no coils fire except the knocker, and the lower playfield GI lamps stay dark. The rectifier, MPU and solenoid driver test points all read normal.

Only the knocker fires and the lower playfield GI is out: replace the rectifier board

Cause: The rectifier board was faulty even though its test points read normal.

Checks

• Check the fuse under the playfield between the flippers and its holder.
• Repin the rectifier board connectors and wiggle them while watching the coils.
• Measure the voltages under load at the playfield, not only at the test points.

Fix

• Replace the rectifier board.

The rectifier board is fed from the transformer; turn the game off before handling it.

Systems

• Stern MPU-200

Games

• Split Second

Related tips

• Rectifier board swap: the white wire soldered to the board is the GI bus (J1 pin 8)
• Rectifier test point reads below its range
• Rectifier board test point voltages
• Rectifier test point ranges with fuse and rectifier
• No +12 V at rectifier board TP3
• Solenoid driver TP5 under 13 V
• What each rectifier on the board feeds
• The three Bally rectifier boards

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