how can I tell if my 7jp4 is dead?

[Adam]

I have to get the transformers out of the chassis, just to see behind them so I can see how they are connected. After looking at the set as much as I did I had assumed the modifications were unfinished, it was fixed to the point where the HV and sweep circuits worked, and he stopped there. It does not seem possible to me to have as much of this set wired in series as it is (at least the 6 rf/if tubes through the video amp), and have it connecting to either the 6v or the 24v transformer and even getting as much voltage at the filaments as it is. If it goes to the 120AC, then as not all of the tubes are still in a series string, and there is no replacement for the ballast tube, then the voltage at these tubes would be too high. I would think if one were to wire the set with filament transformers one would just put all the 6v tubes parallel to the 6v transformer, 12 volt tubes parallel to the 12v transformer, and dispense with the series strings entirely. I was also considering getting a 12v. transformer and doing this.
There should be a schematic of the original filament circuit and the rf section here, later I will try to see if I can draw in the modifications.

[Adam]

Here it is.

[Adam]

I stayed up late last night and figured out whats going on. Now I think this filament circuit should actually work, a quick drawing of what's currently in the set below. It is just a several sets of tubes in series, in parallel with the 24v transformer. Pin 4 and 5 of (V2) the 12AT7 I was talking about earlier have been soldered together, so the tube works just like two 6volt tubes in parallel.
I don't understand why one side of each transformer is connected to ground, as all those filaments which are connected to ground are connected together anyway by wires (Even the ones going to the 6v trans. are directly connected to the ones on the 24v trans. -- this is what confused me for so long). (The drawing simplifies it so you don't actually see all the wires, for example, v10 actually has a wire connecting it to v7 and one connecting it to v8, then there is a wire connecting v7 to v8, then one connecting v8 to the crt and the 24 volt trans, and from that point a wire finally goes to ground ... or something like that ... Once I realized most of the wires were just the equivalent of chassis ground, it all began to make sense.) I would think the extra 24v AC going through the chassis might even cause some problems. I would like to disconnect these from ground entirely and just wire them up one to the other, with no links between the output of 6v and 24v transformers.
Also, all those resistors and caps are just leftovers from the old circuit (with the exception of the one near V11 which was added later to keep those filaments from having 6v too much voltage). I would think they would just be an unwanted drain of power now.
And lastly, the 25L6 audio amp tube was exchanged for a 6K6 and placed on the 6v trans. along with the crt. Is a 6K6 a good replacement for a 25L6 if only the filament voltage is changed? I don't understand why they did not keep the 25L6 and just put it in parallel with the 24v trans. Or better yet, if the 6K6 is a good replacement, put it after V11 and take that resistor out of there. Then use the 6v trans. exclusively for the 7JP4.
Anyway, with the exception of those possible additional modifications, I've decided I like the way the set is (now that I understand it) and am not going to change it from the way it is now.
This also means that with the filaments wired as they are, they are probably not causing any major problems, and I need to think more about what is causing this not to work.