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Can anyone tell me about fused resistors in this circuit?

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Can anyone tell me about fused resistors in this circuit?

Postby AiwaProblem » Tue Jan 15, 2013 8:01 pm

Please help as I have been trying to fix an Aiwa Graphic equaliser GE-Z7000 for weeks now. Basically if you look at the attached circuit I had a fault which had blown the bottom 2SC3328 and taken out the fuse link L1. I have successfully replaced these and the other 2SC3328 for good measure. I now have 2 open circuit resistors R82 and R83 that are green with unrecognisable bands and could be fuses? They are marked as R82 1.8 (NF) 1/4 watt. Does anyone know what I should replace with please?

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Many thanks
AiwaProblem
 
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Re: Can anyone tell me about fused resistors in this circuit

Postby I_Daniel » Fri Jan 18, 2013 1:02 pm

The circuit reads 1.8 while elsewhere the resitors are given in k. I would thus presume that they are 1.8 Ohm resistors.

When the transistor blew excessive current would have flowed through the resistor. First try using an Ohm meter that can read low resistance. i.e a 200 or 500 Ohm setting. The resistors may just be blackened but not "fried"
I_Daniel
 
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Re: Can anyone tell me about fused resistors in this circuit

Postby AiwaProblem » Fri Jan 18, 2013 4:44 pm

I_Daniel,

thanks for reply the resistors are definitely open circuit and I know feel I have found the answer similar to your way of thinking. I assumed as old the decimal point in the resistance is the newer R position so this would be a 1.8 ohm i.e. 1R8. It must be a resistor because of the symbol but the NF threw me. I guess it must be Normal Fuse or something similar?
I then set out to find a fused 1R8 and could not find any but located 1R0 fusibles in packs of 10 on Ebay and for each or R82 and R83 fitted 2 x 1R0 in series. I powered on and the equalizer sprang into life. Research since tells me the circuit is a DC to DC converter something I have not come across before. So all in all an interesting exercise and a good outcome!!!

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