Quote:
Originally Posted by zombie1210
Curtain burner line cord? Sounds ominous.
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Oh yes , it was .
The term "Curtain Burner" comes from the 1930s radios that had a resistance wire built into the line cord to drop the 110 volt AC to the combined (series) 68 volt requirement for the tube's heaters . The 25Z5 and 43 output both have 25 volt heaters , for 50 volts required . Add in the 6 volt requirement of the other three tubes and we add 18 volts to the 50 for 68 volts combined heater requirement . Some sets used a ballast tube (like your set uses) to drop the "extra" 42 volts from the 110 volt line (110 - 68 = 42) and some sets used the resistance wire . The line cord could and did get hot enough dissipating that extra power that fires were started , especially if the line cord was touching something very flammable , like for instance some curtains .
Most folks nowadays eliminate the curtain burner cord and go instead with an AC capacitor to safely (and without heat) drop those extra 42 volts . Since your set uses the ballast tube no such re engineering of the heater circuit will be needed . The one caveat here being that the ballast tube is essentially a light bulb with a tapped element (to provide power for your dial lamps) and is subject to burning out just like any other light bulb is . I would recommend picking up a spare or two of the ballast tube to have on hand since as years go on they ain't getting any easier to find ....