Thomson DT16300 cannot find aerial?

My Thomson DT16300 was working perfectly but today when I switched on the TV all I got was completely black screen with diagram of an aerial at the top. Not a problem with the aerial or the tv as I have replaced the Thomson with another freeview box and everything works perfectly. Does the Thomson have an internal fuse that might be the problem? Manual doesn't address this problem other than saying to check all the connections.

geoff
February 2013