I really don't know any other way to do it other than powering up the
set. Ringing a flyback is not going to reveal a cracked case arcing
problem. What I have done is make 2 test transistors, one with a
damper, one without out of old obsolete TV outputs such as old 2SC1172
metal case outputs, and old outputs from TVs like the GE PC chassis.
Use the original metal mounting plate from an old set that had a socket
like a mid 80s Zenith. Run a foot or two of wiring to the socket. Now
when an output transistor is shorted, after doing all the pre power up
checks, instead of replacing the transistor, I simply run the wiring
from the test transistor to the board and solder. Turn the set on with
a HV probe that has min/max memory in the anode then quickly unplug and
see if HV normal. If arcing happens and the test transistor is shorted,
takes 30 seconds to replace it with another junk TV output. All free.
Works for me. Saves some work, and I've found these old transistors
pretty much will work any TV for a test anyway.