The following procedure was written by Curt Palme.
While I’ve been critiqued for this, there are times where you need to splice
a high voltage (HV) lead due to an arc or to the fact that the HV lead end is
different. Now, before we start, the best way to change an HV lead is to cut off
the entire HV lead and rubber anode cap right at the bell of the tube and
replace the whole lead, but if you’re short on time and don’t have a new lead
handy, this is the way to get arc-free HV lead splices.
You need to get some heat shrink tubing, the stuff that shrinks about 40-50%
when heated. You need a heat gun, although a lighter will work as well.
Start by stripping back the HV insulation, and form as small a connection as
you can. Put a minimum of 5 layers of two or three different sizes of heat
shrink over the HV leads, two or three pieces of heat shrink over each HV lead.
Make sure that each layer of heat shrink is slightly longer than the next, and
allow for at least 1” of overlap onto the original insulation area (see
Solder the splice point so that stress can’t pull the lead apart (see image