You can try connecting the PC monitor, with the same wiring as the inverse of "PC to Arcade Monitor" interface. If the monitor supports 15Khz, it will work. Also, you may want to try an Old CGA or EGA monitor. I beleive CGA is 15Khz, and EGA is 24Khz.
Also, if you get a componet to NTSC convertor from a video supply store, that may work.
P.S. some arcade games can output NTSC. If that is the case, you have got it made.