Help me identify this resistor please

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Ryan Stille

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Feb 26, 2017, 5:21:02 PM2/26/17
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I'm trying to fix an RC battery charger. The charge circuit works, but the discharge circuit does not. I'm guessing this abused-looking resistor might be the culprit.

The black band on the left looks like it has more space than the other bands, so that might be the tolerance, but I don't think black is used as a tolerance band?

From right to left I'm seeing brown, black, silver, gold, brown. This is not matching up well in the resistor charts I'm finding. I tried measuring the resistance, but got no conductivity.

Inline image 1

Ryan Stille

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Feb 26, 2017, 5:32:37 PM2/26/17
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I just found this on http://www.resistorguide.com/resistor-color-code/, in the "exceptions" area.

5 band resistor with a 4th band of gold or silver
Five band resistors with a fourth band of gold or silver form an exception, and are used on specialized and older resistors. The first two bands represent the significant digits, the 3th the multiply factor, the 4th the tolerance and the 5th the temperature coefficient (ppm/K).[/quote]

So that would indicate a .1 ohm, with a black temperature coefficient band.

Greg Hoff

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Feb 27, 2017, 1:41:00 PM2/27/17
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This looks like a fusible wirewound resistor.  You are reading the four bands correctly but black is not assigned to a temperature coefficient value.  Manufactures tend to use unassigned colors for their own purposes.  You would need to look at the datasheet from the manufacturer to interpret the meaning. 

I can't tell what the power rating of the old resister is but it looks relatively large.  I'd try replacing it with http://www.digikey.com/product-detail/en/yageo/FKN200JR-73-0R1/0.1DMCT-ND/2813098.  If it blows again, then you'll need to track down the cause or if you think it is operating correctly try a larger power rating.
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