Sounds like the z amp is on the fritz, but I don't know that 'scope well.
For folks who really know their Tek. 'scopes, go to the Tekscopes group on
Yahoo.

http://groups.yahoo.com/group/TekScopes/

It's probably something quite simple ...

Dave
wrote in message
oups.com...
I've got a tek 465 oscilloscope that has a weird intensity problem. On
powerup, the intensity gradually increases as one would normally
expect, but it continues to rise until the whole room is illuminated
with an eerie blue glow. The intensity knob has an effect on the trace,
but it only goes from ridiculously bright to obnoxiously bright.

At the point where I estimated I'd had my year's worth of x-rays, I
turned the power off. But I think I did check a few voltages on the CRT
circuit and didn't see anything unusual. It's been a year or so since I
have messed with it.

I have heard legends about CRT's shorting internally and causing this
problem. Is this likely in my case? And how would I verify that? I did
not observe any continuity between any of the CRT neck pins, with the
exception of the filament, of course.