After changing some bulbs and lowering the playfield, the saucers, drop target and ball pusher stop working, and a flasher by the right spinner now fires the knocker on every spin.

After a bulb change, coils dead and a flasher fires the knocker: blown supply fuse

Cause: A blown fuse on the power supply board feeding that group of coils. A socket probably shorted while the bulbs were being changed.

Checks

• Use the manual to find which supply all the dead devices share, then test that fuse out of its clips.
• Check the backs of recently touched sockets, and harness wires that moved when the playfield was raised, for anything touching.

Fix

• Replace the fuse with the correct rating and check for the short that blew it.

Systems

• Data East CPU Version 3

Games

• Lethal Weapon 3

Related tips

• Power supply board fuses (late games)
• Dead or intermittent circuit from a cracked fuse clip
• A 520-5047-02 supply can stand in for a 520-5047-01
• Dot matrix shows lines or lights solid, and no CPU lamps work
• DMD shows lines or garbage and no controlled lamps light
• Adding jumper wires across DB1 and C4 (520-5047-00/-01/-02)
• Low-power solenoid voltage drops to under 5 V
• No or low +5 V from the power supply

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