The game sits in attract mode. Pressing the start button makes the DELUXE letters and pop bumper lamps flicker instead of starting a game; touching the back of the start switch sometimes lets a game start, but those lamps still misbehave.

Start button flickers lamps but no game starts: loose aux lamp driver connection

Cause: A loose connection at the auxiliary lamp driver board, upsetting the lamp and switch signals.

Checks

• Check the outhole switch registers in switch test so the game knows a ball is home.
• Reseat and inspect the connectors and wiring at the auxiliary lamp driver board, looking for a loose or burnt pin.
• Repin any connector with loose or discoloured contacts.

Fix

• Repair the loose connection at the auxiliary lamp driver board.

Systems

• Bally MPU AS-2518-35

Games

• Eight Ball Deluxe

Related tips

• Lamps on the auxiliary lamp driver board do not work
• Controlled lamps flicker or stay out after fitting a replacement lamp driver with LEDs
• Lamp driver, auxiliary lamp driver and display driver test points
• Auxiliary lamp driver boards: SCR to connector pin
• Auxiliary lamp boards drive special backbox lighting with MCR106 SCRs only

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