Sick Scope
 

My Tek 466 scope decided to misbehave. It will not display the horizontal
beam unless I press the beam finder. When I do it displays whatever I'm
looking at(eg: 7 Mhz sine wave) properly.
I'm quite familiar with this scope, but possibly doing something stupid.
Does anyone have any idea as to what the problem could be?
Thanks in advance for any light you can shed on the problem.

Laurie