How to use this ROM image with your PCB:

Your Ketsui PCB has one 27C160 EPROM at position U38. Take the ROM file from the zip archive you downloaded from here and burn it to an EPROM of the same type using an EPROM programmer. It should work by reburning the old EPROM too, if it is erased properly first.

Hint: A useful method to remove an eprom from a socket would be to stick a flat screwdriver between eprom and socket and then to rotate it carefully until it lifts both sides of pins out of their slots. Always keep an eye on the correct direction whenever you place a eprom into a socket (Look out for that small gap at one side of the chip. Find the same gap imprinted on the surface of the PCB)