Line collapse is a pretty rare fault. I would definately have it checked by an engineer as it can often be caused by faults affecting the safe use of the tv.
An engineer might first check the four thick coloured wires running to the scan coils for a detached connection. Especially they will check the plug/socket at the circuit board for signs of severe dry joints causing smoldering/burning to the copper print or melting of the plug/socket. They will also be on the look out for fractures to the printed circuit board.
There are lesser problems that could cause line collapse, but in my experience those are favorite.
Cobweb, July 2006
