I have a great Tek 2213 that was purchased form a TV station. The
scope is in great condition, but CRT is very dim. IIRC, I've read
that these scopes had a slightly high filament voltage resulting in
short CRT life, and there was a mod that Tek did to fix this problem
by removing a few turns on the XFMR. Is this right? I also remember
someone saying that there was a marking on the back of the scope or
the xfmr if they had been modified. Well, I found a replacement CRT
with plenty of life left in it, but I don't want it to fail
prematurely again. Is this a user modification, or is it pretty
lenghty? Any info on this subject appreciated.

Thanks,
Steve