I have a 465B that has been perfect up until a few days ago. After the scope is on for about an hour, the trace begins to slowly drift to the right and then is off the screen in about a minute. Beam finder works but trace is off the screen.
Power it down for 30 minutes and is ok again for an hour.
Anyone seen this problem before or have an idea what it could be?
Sounds like the horizontal output drive going 'thermal' on u. Use a can of cold spray on the drive transistor and neighbouring components, while observing the display, that should identify the specific area u have to sort out.