Testing a Bias Resistor - Printable Version

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Testing a Bias Resistor - Tucker - 10-09-2017

I'm working on a Philco 37-630T that has a "bias resistor" that looks like a 3 section series (candohm like) resistor.
My question is , how do I test this resistor ? Does one end of the meters probe go to ground and them I measure the resistance on each lug?  Or do I test section to section?

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RE: Testing a Bias Resistor - Raleigh - 10-09-2017

Normally you think of a candohm as being 3 resistors in series. You measure resistance between each lug and the lug next to it. You might have to check out the wiring to see which pair of lugs represents which resistor value on your schematic. Often for bias resistors, one end lug is wired to ground (and the minus side of the output filter cap) and the other end lug goes to the center tap of the power transformer, but I'm not looking at your schematic. Yours might be different.

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RE: Testing a Bias Resistor - Radioroslyn - 10-09-2017

Hi and welcome,
Service info can be found here  http://www.audiophool.com/Philco.html
Nostagair skipped it.

>how do I test this resistor ? Does one end of the meters probe go to ground and them I measure the resistance on each lug?  Or do I test section to section? 
Typically you would want to test each section. In some instants they have been known to short to the chassis when hot. If this happens it causes the - bias voltages to go away. You can just check to see if the - voltage are correct.

GL

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