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Ralph Mowery Ralph Mowery is offline
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Default How do you test a Selenium Rectifier?

In article ,
says...

How do you test a Selenium Rectifier?

Yes, I am aware that they should be replaced, but on preliminary tests
of this 1956 Zenith tube AM-FM Radio, I want to know if it's working. My
digital multimeter shows 1meg in one direction, 2.5 meg the other way.
NOT DISCONNECTED FROM THE CIRCUIT. To me, that seems bad, but I have not
worked with one of these in many years, and never had to replace one in
the old days. My meter was climbing, probably from the filter caps.
during this test.





The same way as with any other diode. However the selenium drop about a
volt for each plate that is on it. Each plate is only good for about
25 volts , so you may have 5 to 10 volts to overcome. Therefore most
meters will not have enough voltage to over come that drop.


Get a voltage source of around 10 volts or more (maybe even a 9 volt
battery will be enough) use your meter on the voltage scale and put hte
battery , diode , voltmeter in series. Then turn the voltage or diode
around and measure again. There should be a couple of volts dropped one
way and many more (almost all) the other.