There are three ROM files, from two PLZ153W units I have:
- First unit comes with the GPIB card option, so there are two ROMs from it: one from the main/CPU board, and one from the GPIB board
    Kikusui_PLZ153W_main_board_ROM_ver_1.08_AM27C020-120DC.bin
    Kikusui_PLZ153W_GPIB_board_ROM_M27C256B-15F1.bin
- Second unit comes with no options installed, so there is only the main/CPU board ROM
    Kikusui_PLZ153W_main_board_ROM_ver_2.00_AM27C020-120DC.bin

