The pop bumper lamps, the lamps by one target bank and a few others on the left never light, though GI fuses test good and the GI connectors have been replaced. Dead sockets show continuity between their two tabs.

Pop bumper and target GI lamps dead: a previous owner's added socket shorting

Cause: A previous owner had run extra wires under the back rockwork to an added lamp socket, and the botched wiring was shorting the GI string.

Checks

• Check AC voltage at the GI connector pins for that string on the power driver board.
• Check the GI fuse out of its holder.
• Look for wiring that doesn't match the manual and for continuity between lamp socket tabs, which means a short.
• Unplug the GI connectors one at a time to find which string is affected.

Fix

• Remove the added socket and its wiring and restore the GI string to factory wiring.

Systems

• WPC Fliptronics

Games

• Bram Stoker's Dracula

Related tips

• One GI string dead with good fuses and connector
• Upper GI fuse blows after a pop bumper rebuild: solder blob inside a new socket
• A lamp row very bright or dead
• A few unrelated lamps never light
• Hologram lamp dead: its 12 V wire is loose at the flipper opto board
• GI string still dead after replacing J115: broken through-hole, add a jumper
• Part of a lamp row or column stays off
• One controlled lamp out while the rest of the matrix works

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