i found the same to be true with my 43" sammy dlp. pretty dissapointing since i don't use those inputs. what i have found is that my cable box coax output is always active so if i run a standard coax cable to the antenna input, i can have a hd source in the big part and see the "cable" picture in the PIP window that is set to antenna. though you can't switch them, it is better than nothing.