After the power driver board was removed and refitted, the game will not boot. GI lights come on and the display sometimes shows the game name, but none of the LEDs on the CPU board light, and one LED on the driver board blinks.

Won't boot after a board swap, CPU LEDs dark: loose 5 V wire in the CPU power plug

Cause: While unplugging the driver board connectors, a wire in the CPU board's 5 V power plug was snagged and pulled loose from its pin in the housing, so the CPU had no 5 V. The blinking driver board LED only meant there was no communication from the CPU.

Checks

• Measure 5 V at the driver board test points.
• Measure 5 V at the power input plug on the CPU board; if it is missing there, inspect each wire in that housing for a pin that has backed out or broken.
• Leave the 5 V adjustment pot alone; it is factory set and turning it only hides a wiring fault.

Fix

• Re-seat or re-crimp the loose wire in the CPU power plug (replace the housing and pins if they are worn).

Systems

• Sega/Stern Whitestar

Games

• NFL

Related tips

• After cleaning the cabinet most coils are dead and the display goes dark: reseat J16
• Whitestar: I/O board blanking LED flashes, lamp rows 1 and 3 dead: data bus short
• Game keeps resetting with blank display and blinking lamps: faulty 6264 RAM
• F7 blows at power-up: flasher socket tabs touching, which also shorted Q27
• Game faults after the CPU battery leaked: corrosion ate traces and chips
• Whitestar flipper weak or dead after a MOSFET swap: fake part, test with TPL1
• One flipper flips but has a weak hold and drops when hit: bad transistor at Q16
• Resets when the flippers are used: arcing flipper coil, then bridge rectifier BR21

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