Blunderof the Week

[Tubejunke]

Originally Posted by old_coot88

Polarity might (or might not) matter. If it's backwards, the IF stage might go into oscillation. If it does, just reverse one coil or the other to correct it.

I'm pretty certain that polarity will not be a concern.

[old_coot88]

Originally Posted by Tubejunke

I'm pretty certain that polarity will not be a concern.

Probably not, much less so than for the 1st IF xfmr.

[Winky Dink]

Well, I've finished replacing components, I have the tubes, and I'm almost ready to power up this set. The project is coming down to the wire (pun intended). My last issue is the line cord/resistor combo represented in this part of the schematic.



I couldn't figure out where the 566 ohm resistance was until I started to autopsy the line cord.



The resistance wire, roughly 25 feet, taps into the line cord near the plug end and emerges as a third conductor inside the chassis. I suppose this is the equivalent of a wire-wound resistor to get the rectifier's heater voltage down to about 35V.

I don't want to use this line cord because the insulation is so brittle that it cracks and falls off when it bends. My question is, can I replace the 566 ohm resistance with 566 ohms between the plate pin and the heater? And if that's a good plan, then what power rating would I need? By chance, I have a couple of 560 ohm 7W resistors.