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?