problem with Toshiba model vtv2134 combination 21" TV/video recorder?

since the world soccer cup, there has been a line across the screen of our Toshiba model VTV2134 comb.21"TV/video recorder with the area above it, constituting about one-sixth of the total picture area, lost to view .
So when a footballer kicks the ball upwards, it seems to hit this line and suddenly come back down.
I had thought it might be the horizontal hold at fault, but find no ref to this in the instructions
The picture is very disconcerting to watch.
Any solutions please?

alan dudeney
January 2007