And why is the outside of the cap high tension, is it because of the
black stuff or is the cap perished?

Unplug the tv and discharge the high voltage as instructed. Clean the
rubber cap and around it to see damage better. You will find very
tiny pinhole or a arc track (by the carbonization) in that rubber or
under that rubber that HV managed to work itself out and go zzzzt
noise. Then remove cup by getting both sides of cup up and squeezing
the clip with screwdriver to get one barb over the anode cavity lip
then another barb will be easier to come free.

The rubber cup (cap) is replaceable. We sometimes have to do this for
any reasons. Ask for one from used pull especially one from recent
RCA. A good tech shop should keep leftover new stuff like I do
especially when I'm replacing flyback transformer and the HV lead and
cup is susplus and keep extras in a box. This has a metal dished cup
clamping on the wire by rubber tension. Work the little disc out and
pull the wire out. And cut the old one off the HV wire if you have
enough length otherwise get old cup apart (cutting the rubber) if
there's not enough excess length to this HV lead. You want the bare
wire enough for the metal clip. The rest of insulation should be all
the way into the new cup. Lube with silicone dielectric grease to
make pushing wire into new cup easier.
Then put the metal disk same way in and work it in. Want the lip of
rubber to get over that disk, holding it in therefore clamping that
bare wire.

Also clean the new cup and lead, Clean CRT area out to 2" radius from
that anode cavity. 99% alochol is good for this clean up. Put bit of
silicone dielectric grease on that CRT around the anode cavity where
the new cup will contact (just a ring of thin layer will do). Use
washed hands, one handed holding bent back to let you hook one side of
barbs and one clean dull small flat screwdriver in other hand to get
other barb into hole and push it in. Both barbs should be hooked
under that anode cavity. Let go of rubber and massage it to seal
properly. Go carefully.

The HV lead from the flyback transformer is non-removeable.

Cheers,

Wizard



I think I assumed (wrongly) the outside of the cap was ment to be HT.

I am a little more worried now.




underneath is a metal clip that clips into a little metal pot
cast in the glass of the tube. Once you lift the edge it'll be obvious how
to remove it.




(the suction cup
thing) clean the tube well, then smear the rubber with some dielectric
grease you can get at any autoparts store. You need to discharge the
tube
first, just connect a wire to a screwdriver, and connect the other end
to
the metal ground strap around the back of the tube

I am not sure I can find an obvious ground, there is very little metal
visable.
The four corners where the tube attatches to the case seem to have wires
attatched to then, I assume these would be earth?
There is very little other metal to be seem.


The back of the tube is coated with a dark gray conductive coating, there
should be some sort of ground contact that connects to that, often there's
a
metal strap around the back of the tube.


Yes I can see a braided metal strap held round the tube by wires which
appear to connecte to the afore mentioned corners, it helped when I
used a decent light to see with.


Thanks again