A common problem with this symptom is that the input was inadvertently switched from "Air" to "Cable", which would result in no channels being found. See if that helps.
If not, keep mep posted.
Living in the city, we are pretty close to the TV stations, still the tuner cannot catch a single channel. Recently a friend bought an external antenna, and we tested it and could catch all signals. Even after removing the antenna, the channels were still available.
After a while, now the TV cannot tune any channels.
What is the use of buying a unit with a tuner if it cannot catch a single channel?
What is samsung doing to fix this problem?
I have other friends staying close to my residence who can catch digital HD signals.
Any response from Samsung guys before i recommend others to avoid samsung at all cost.
Irritated Samsung customer (and maybe soon to be a avoid-samsung-at-all-cost customer)