Atari Jaguar Controller Port D Flip Flop (74HCT374)

If you are having issues with groups of buttons on your Atari Jaguar, such as C, 8, 5, 2 and 0 all not working at the same time (usually groups of 5 to 8 buttons) then it is typically this U18 flip flop or the Line Drivers (we sell that chip also).

There is one of this flip flops handling various different button sets for both ports, and it is labelled U18.