03-29-2014, 08:53 PM
If a radio with a selenium rectifier is working, I usually measure the DC current through the selenium before I replace it. Then I use a resistor that will give me the same current.
The Philco D-655 I'm working on now took an 82 ohm resistor. The resulting DC current when plugged into 123 VAC is about the same as the original when plugged into 117. Power dissipation was .3 watt, so I used a 1 watt resistor. I tried it with 200 ohms, as BrendaAnn suggested, and that worked fine too, but the current was a little low, I thought.
I've sometimes put a couple of layers of heat shrink on the silicon diode leads and then fish those leads through the two terminals of the selenium rectifier. Then I solder the leads onto loops on the ends of the silicon diode leads. That takes the selenium out of the circuit but sort of preserves the appearance. Usually I do what BrendaAnn does and use the selenium mounting hole for a terminal strip.
The Philco D-655 I'm working on now took an 82 ohm resistor. The resulting DC current when plugged into 123 VAC is about the same as the original when plugged into 117. Power dissipation was .3 watt, so I used a 1 watt resistor. I tried it with 200 ohms, as BrendaAnn suggested, and that worked fine too, but the current was a little low, I thought.
I've sometimes put a couple of layers of heat shrink on the silicon diode leads and then fish those leads through the two terminals of the selenium rectifier. Then I solder the leads onto loops on the ends of the silicon diode leads. That takes the selenium out of the circuit but sort of preserves the appearance. Usually I do what BrendaAnn does and use the selenium mounting hole for a terminal strip.
John Honeycutt
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