how can I tell if my 7jp4 is dead?

[Adam]

Thanks for the schematic. It did seem odd to me that you could get by without a hv rectifier. But it wasn't shown on the tube diagram glued inside the cabinet, neither was that 25L6 for that matter. And there were no visible holes to vent heat in that metal box, and as I had never seen a 7" electrostatic set before I was willing to believe about anything. It is the Motorola TS-4J, 1948 is stamped on the back, but sams gives a date of 1949 for the TS-4J? What's going on with the only 8 positions on the tuner, are some of the channels doubled up?, I can't read the numbers on the cabinet anymore.
I see the audio section actually branches off after the video amp tube, so the trouble could be in either the RF, or IF sections. It still seems to me like tubes not working, once I had a set where the only thing broken was that all 3 IF tubes were bad, a much newer set, but it displayed exactly the same problems.