Cannot tune tv onto new channel,76 says invalid format, can get all other channels have soundbut no picture

C. If 78 is not on the channel list or displays as a blank screen with sound only or listed as " audio only" or " "no video" you will find that channels 7flix and 9HD and Ten HD are the same. This means that your television is not compatible with the type of broadcast signal that these three channels use.
To be able to receive these channels you will need to purchase an adaptor for the television. This may be a Set-top-box e.g., Freeview or a PVR (Personal Video Recorder).Note: A limited number of models may be compatible but have the option to do so disabled. You can adjust the settings in certain models264 of 2009/2010 Panasonic sets via "Add MPEG-4 AVC Channels" in the menu. Some other brands may have similar settings available in their tuning options menu. Thanks to http://forums.mediaspy.org/

Although channel 76 is starting transmissions on Sunday 25 feb press releases and statements from channel 7 state that channel selection and programming for sets may not be effective until Wednesday 2 march
if you have the latest digital led you beaut tv , it will still not select until 76 comes on line as there is nothing to select ( there has to be a signal transmitted for the tuner to find it)
ask the question again if you are not successful after Wednesday