Does anyone know what this component is, I got it from a metal detector board when powered up, it was smoking away slowly. Roughly it took about 30secs before it has visible smoke. I measured it to have about 9ohms.
Keep in mind that it is not because this resitor started smoking it is the culprit of the failure. Something else may hav given way and caused overstress here.
Where exaclty this component was, in metal detector board....
If it is at entry point of power supply and a capacitor with it then it could be inductor for filtering purpose. OR it could be Fuse or fusable resistor (normally low value) to limit the max current IN.
If it is in series with metal detecor coil... then this component may be a resistor to control the coil current using feedback...
As it was smoking 9ohm value may not be ture. If this component is at power entry point... then may be metal detector circuit is sinking more current..
As you told it took around 30 sec to smoke.... then I think your inductor coil is saturating slowly and taking max current.