[mikethedruid]

Jake, I've seen rectifier plates glow red when the electrolytics have gone bad! I doubt that extra capacity on the filter condensers was a problem with the 51x17. It would cause slight extra current through the transformer and rectifier while they were charging up at the beginning, only one or two cycles, a fraction of a second, but after that be normal, and actually give better filtration to the DC. I'd look for another problem there. As for the isolated condenser, it is really pretty clever. What the circuit design does is put one side of the rectified DC negative compared to chassis, and the other positive compared to chassis. It saves needing a double power supply. Much later designs use a cathode resistor with a bypass condenser to cause the grid to bias negative with regard to the cathode and smooth out the bias voltage by bypassing any signal from the voltage, but this is not as good, and does not give as steady a bias. Nope, those old designers knew what they were doing when it comes to tubes. My T8-18 RCA uses a similar set up to the Philcos to produce the negative bias and positive plate voltages. That's why it has the two candohm resistors. If you have a bad power transformer, I wish you luck. You can get them rewound and rebuilt. I'm not sure where, never have had to have it done, but I'm sure someone here knows where. Antique Electronic Supply also carries quite a few replacement transformers, one of which might work.