snowy dtv and no cable

im haveing a problem with 4 of my receivers  over the past 6 months one by one my receivers went down  my cable stopped working and when i put my dtv on it is all snowy but when i dissconnect my dtv and just put my cable on the  tv ,the  tv works fine when i run the sat test it all passes except the phone line is not plugged in  is this a receiver problem

                                          thank you