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I can't imagine how your radio passed the dim-bulb test if a resistor started smoking when you plugged the set directly into the line. There is still a major problem with the power supply, especially if the 5Y3 rectifier tube is running hotter than normal (as you mentioned in a previous post; you also mentioned the tube was "sparkling", which means trouble as well). The resistor you mention is burning for exactly that reason--the component is being called on to handle more current than that for which it is rated. Did you replace the filter cap when you recapped the chassis? If so, that rules out a shorted filter and leaves either a shorted high-power tube (such as the 6V6 you mentioned) or, worst case, the power transformer. When a resistor burns and smokes in any piece of electronic gear, you can be sure there is a serious short somewhere that must be corrected before the equipment is used again.
The 5Y3 rectifier running hotter than normal is a danger sign as well, as I mentioned above. There is one other possibility--I don't know whether or if this would apply to a transformer-powered radio, but I'll put it in here anyway. Does the dial light work when the radio is switched on? If not, I'd replace it ASAP. I mention this because in some radios, the pilot light is part of the power supply; for example, I have a 1951 Zenith H-511 that uses a pilot lamp as a current limiter. The lamp glows very dimly when the radio is switched on from a cold start, then brightens as the set warms up. When the tubes are fully warmed up and the set starts to play, the pilot light is at its maximum brightness. If there is a short anywhere in the power supply (or if the 3-section electrolytic filter cap is deformed from years or decades of disuse), the pilot light will burn out with a bright flash. If the radio is used without the pilot lamp in the circuit (e.g. the bulb is burned out), the 35W4 rectifier tube will glow brighter and run hotter than normal, leading to premature failure of the tube.
Note that the foregoing applies to series-string radios with pilot lamps; as I said earlier, I don't know if the same applies to transformer-powered sets. Again, that the 5Y3 rectifier tube in yours is "sparkling" and also running hotter than normal, not to mention the burning resistor (which is probably a large power resistor in the supply circuit, near the transformer), are unmistakable indications of a very serious short in the power supply.
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Jeff, WB8NHV
Collecting, restoring and enjoying vintage Zenith radios since 2002
Zenith. Gone, but not forgotten.
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