First I would eliminate Tuner, IF problems and check if TV works correctly in RBG only. Do on-screen menus appear clear? Does Teletext appear clear, (if available)?
Do you have any other external video equipment connected to the direct AV inputs to the TV? eg. DVD, Decoders etc.?
If you do, disconnect them and try operating the TV off an RF signal only.
Conversely, if you don't have any external AV equipment connected, check if the TV picture is OK off a direct Ext. AV Input. This will eliminate Tuner/IF problems.
Cobweb, November 2004