First, here's my question: How do I discharge the CRT and other high-
voltage components so I can safely resolder the Vertical IC on the
main circuit board of my television?

Here are the details of my situation (long!):

I have a Zenith 27" television set circa 1995 that works perfectly,
for the most part. The only problem is that, as it's warming up
following power-on, it goes through three distinct phases:

1) A normal picture, usually for 2 or 3 minutes (shorter duration on
warmer days, longer duration on warmer days)

2) The lower half of the picture collapses to a center horizontal
line, and the top half remains mostly intact but is pulled downward a
few inches toward that center horizontal line (this usually lasts 5 to
10 minutes, depending on room temperature)

3) The picture twitches a few times from normal to collapsed, and
finally settles in at a perfect picture, remaining there until I turn
off the set.

I removed the back cover from the set to see what's going wrong. I'm
guessing there's a cold solder joint or other 'mechanical' problem
with the Vertical amp section on the main circuit board. Sure enough,
when I very gently touch (using a long wooden chopstick!) the S-shaped
heatsink that holds the Vertical amp IC, I can make the problem come
and go at will.

So now I'd like to resolder all the pins on the Vertical IC, and I'd
like to do it safely.

I'm good with digital electronics, but a total newbie at television
repair. I understand that high-voltage safety precautions are needed
when repairing a TV, so I'm hoping to get some help in this area.

Can anyone lend me some tips and advice here? Any help is greatly
appreciated!

Dave