[DaveWM]

neon will not light up around the anode, needs the AC not the DC. It may flash but will not stay lit. It could be a bad HV rectifier tube. I would just pop for a HV probe, if you are going to own vintage TV's you need to learn how to work on them and the tools to diagnose problems. If the HV is not there and you have a good arc at the plate cap of the HV rec tube then a good chance the problem is the HV rec tube.

There is no tripler used on tube portacolors, maybe a focus divider if you have the high voltage focus set. should not lite up around that either, again DC.

neon should lite up around the horz out tube, the top of the HV rec tube and anywhere near the fly.

If HV is there, I would look at the CRT pin voltages as mentioned for where to look next.

Not sure about this, but on reg color sets you need the focus voltage or the raster goes away. With the high focus voltage PC's maybe the same in which case you will need to confirm there is focus voltage at the CRT pin (if the other CRT pin voltages look good). I use a simpson 260 5000vdc to check focus voltages. you can also use the HV prob as well for focus, just not as good resolution as the simpson.

IF focus voltage has gone away, then I would look at that divider off the HV anode.