More sleuthing time today. I tested all the tubes heater circuit individually and they tested good as expected. Next, to eliminate the possibility of a cathode to filament short, I replaced all 5 tubes one by one
carefully watching the 35W4 and killing the power before it fries.(waiting for a variac) All tubes warm up quickly with the same intensity (including the 35W4), then after around 8 seconds, the rest remain normal, and the 35W4 quickly brightens up as the heater filament goes over voltage accompanied by the first barely audible buzz from the speaker. The 6v panel light replacements haven’t arrived, but in the short term, I don’t think that matters too much as it burned out at the same time as the first 35W4, so it’s not the cause, just another casualty. I am sorely tempted to reinstall the shorted cap again to see if the radio will work again as it was fine albeit garbled on the audio before I ‘fixed’ it. Lastly, I have not replaced the 5 caps? resistors? contained in this device (pic below) because I read these are usually o.k. Should I go there next?
