I have TV model LT32J300 and I can not turn the autoscan feature on. I tried menu, then TV but the functions TUNER, AOTOSCAN , ADD CHANNEL, EDIT CHANNEL, GUIDE are off, they are not lighted and the screen shows NO SIGNALl even though it is connected to an antenna.It works normally with cable by comcast. I need to view some ethnic channels . Please advise how I can correct this???