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component identification aka resistor?

turbobridge

Jul 13, 2013
4
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Jul 13, 2013
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I am working on a fender audio mixer amp . The component in question looks like a flame proof 2 watt resistor but the color code is strange . It measures 3.1 ohms on ohmmeter. Color bands are orange, gold, gold, violet, and yellow. This part was retro fitted on the pcb. It comes right after the bridge that supplies power to the preamp mixer section of the unit, One on each leg of power leaving bridge. The trace was cut and component makes the connection. I assumed it was to correct voltage? The mixer amp works, but not exactly right, with them in it. One of them heats up and has a higher ohm reading (4.3) (hot enough to turn brown) Replaced them with a 3 ohm resistor and the fuse blew when turned on. This happened last night and I haven't got any more fuses as of yet and haven't checked for pilot error on soldiering yet. But could this be a special component that is not a resistor. Any help would be appreciated Thanks
 

csmith

Jul 13, 2013
4
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Jul 13, 2013
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It could be a fusible resistor, and so you should proceed with caution. It looks like fender has downloadable PDF schematics on their website. Check there, or if you can post the exact product you are working on, and a picture of the resistor in question, I might be able to help you identify it.

As for the color code, it's 5 band with reliability. You have the colors backward. It's a 4.7 ohm, 5% tolerance, .01 % / 1000 Hr reliability.
 

turbobridge

Jul 13, 2013
4
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Jul 13, 2013
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Thanks for the help csmith. I believe you are right. Looked it over again yesterday and the resistors are between the transformer and bridge so that makes more sense to me now Thank you for the identification.
 

elebish

Aug 16, 2013
177
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Aug 16, 2013
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177
csmith is correct. Resistor values in that circuit are critical and do not use a wirewound resistor as those will create an impedance (inductance) with ac being applied. This is especially true when the PS is a switching type. Ed.
 
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