Blown smd fuse/resistor

Discussion in 'General Electronics Chat' started by Marc0, Oct 13, 2012.

  1. Marc0

    Thread Starter Member

    Nov 28, 2011
    42
    1
    Yesterday I received a synth with very low output level and no headphone output at all.
    Googling around to find something related, I have found that the problem is a smd resistor which is placed between the PSU (DC 12v 0.5a)and a pair of audio amplifiers (5532 dual opamp for the main outs - LM1877 for the headphones out). Basically the resistor is blown, so the circuit is open and the amplifiers have no supply (5532 has some, via its feedback resistors).
    Now, someone repaired the fault just placing a simple wire instead of the resistor, but I'm afraid to do so, because a spike could damage the amplifiers...
    The synth support told that the resistor should be 6.8 ohm, 1/4 watt... But I'm not sure, because mine is burnt and the first digit is a 5, not a 6...and the component metric is 0805...which usually is for 1/8 watt resistors.
    What should I do?
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,969
    744
    it may be a 5.6 ohms resistor then,replace it with either a 6.8 or a 5.6 ohms, it wont do any damage,all the resistor is doing is lowering the supply to the headphones amplifier to prevent over power.
     
  3. Marc0

    Thread Starter Member

    Nov 28, 2011
    42
    1
    Using my camera I took a photo of the resistor... Its code is 5R10 although between the "R" and the "1" there is a burnt hole. Does power rating matter? Those small resistors (0805 form factor) seem to come in 1/4 watt or 1/8 watt rating...
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,969
    744
    then its 5.1 ohms 1/4w.
     
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