After replacing a 7180 display driver chip on the master display board (to cure one missing segment), the master and player 1 and 2 displays go completely dark.

Williams System 3-7: all displays dead after replacing the 7180 driver: fake chip

Cause: The replacement 7180 was a re-marked counterfeit. Clues were a date code years after the part was made and printing that looked painted on.

Checks

• Look at the chip's markings and date code; a too-uniform painted top is suspect.
• If the old chip only had a segment out and the new one shows nothing, suspect the new chip.
• Check the display glass for a shorted segment, which is what usually kills these chips.

Fix

• Fit a genuine 7180 from a trusted source.

Display boards carry high voltage; work on them unplugged.

Systems

• Williams System 3
• Williams System 4
• Williams System 6 / 6A
• Williams System 7

Related tips

• Four digits missing on the player 2 and 3 displays: bad driver IC12 on the master display
• Bottom segments missing and master display resistors burning: shorted display glass
• A segment missing on a score display
• UDN display driver chips
• Score display driver chip substitutes
• Score displays weak, dim or dead with fuses good
• Display completely dark with high voltage present
• Display driver board versions

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