Infrared receiver assembly in the black plastic housing with a blue circuit board used on many late model Bally and Williams playfield mechanisms.

Reference:

A-16909
B-79711 is the set of Receiver with housing and Transmitter with housing assemblies.
A-14232 is the WPC System opto InfraRed receiver board without the black plastic housing. You can unscrew the bad board from the housing and replace with the A-14232 board.