how can I tell if my 7jp4 is dead?

[Adam]

I changed that tube socket, all the electrolytics, etc. The tv more or less works good now.
I moved the filament wiring like I said I was going to do earlier, putting the 6K6 on the 24v trans, and it turned out only to get around 3.5 volts and the sound was to low, so I put that resistor back in and put the 6K6 back on the 6v trans.
None of the local electronics shops had the 6kv caps, so the HV filter cap is still one of the old ones, and for the vert. sweep coupling I am using ceramic caps in parallel. I have to readjust the vert. hold whenever I change the channel.
The 7jp4 is weak, the picture is clear, but on the dim side, and if I turn the brightness up I get the vert. retrace lines.