Lost lower channels below 200

I have 3 receivers, on only 1 I have lost the lower channels, basically those below 200. The other receivers all function correctly.  I have reset this one several times, and refreshed it several times.  Nothing seems to help.  I will crawl under the house to check cables, buy don't think that's the problem as channels above 200 all come in fine. I do have a multi switch between the dish and TV's with a unused output and will try switching the cables.  Any other suggestions????