The three controlled backbox lamps (Tilt, Same Player Shoots Again, Game Over) never light, even in lamp test, and LEDs there ghosted. The sockets show only about 1.7 V.

Tilt, Game Over and Same Player lamps dead in the backbox: cut lamp bus wire

Cause: The thick blue lamp supply bus wire feeding those sockets had been cut and was hidden behind a wire clamp on the back of the lamp panel.

Checks

• Measure the common feed at one of the three sockets against the ground braid; with no proper supply voltage none of them can work.
• Follow the bus wire along the back of the lamp panel, including under clamps.

Fix

• Reconnect the cut bus wire.

Games

• Gamatron

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