Help needed with my tm 6900 hd combo

[Nectar]

I am watching sport on 15 w on espn2 syndication, i have asked this question before, the picture keeps on flickering, i was told to change in settiI see, you don't watch them, now that there shitngs from pal to ntsc. I have looked in settings on my tm 6900 hd combo but their's nothing there that enables me to change to ntsc, any help would be much appreciated.