I've bought an rf modulator box to get the scart output from my digibox into
a television that only has an rf-in, all seems to work fine except when the
picture brightness is very light (when the screen goes white with just black
text for instance). The picture seems to have a kind of effect I can only
compare to poor tracking on a vcr in that the picture is offset to half way
down the screen and this flickers intermittently between that position and
where it should be. Could someone suggest why this is and what I can do to
remedy it?