Help to I'd component?

Hi all,
Could anyone I'd the part in the picture,I think it's a resistor but can't find any similar?? Its the white one with a grey band and dot

If you look carefully under the component at the pcb, you'll see that's it's a diode.

It's a fairly common diode style as well, they are usually Schottky rectifiers.

Thanks for info Nigel, if I were to order this how do I get a part number and where would I purchase one?

Unless you know the voltage and current rating, I'd try digikey or mouser.

ferox100 said:

Thanks for info Nigel, if I were to order this how do I get a part number and where would I purchase one?

Click to expand...

Too little information - you need one to do the job that the current one does - I'm presuming you know it's faulty?, and that it's probably S/C (and that you've removed it and confirmed the rectifier is short, and not something else on the board?).

It doesn't need to be that shape (I don't recall ever replacing one with one of the same shape), but you need to know what it's doing in the circuit, so as to have some clue what type of specification it needs to be.

So for a start, have you (carefully) removed the rectifier and confirmed it's 100% faulty - you can't check it in-circuit with any degree of accuracy. Next what is the device it's in, what part of the circuit is it in, and how about posting a larger picture of the board to give some context.

I used to have two component draws where I used to work - one labelled 'large Schottky rectifiers', and one labelled 'small Schottky rectifiers' - with those two I could replace any failed Schottky rectifiers I ever came across.

Thanks for the reply, it's a CDI ignitor unit from a motorcycle and I honestly don't know exactly what I'm doing, I've passed it on to a friend who also mentioned I needed a schottky diode/rectifier that has a quick reaction time as it controls power to ignition coil. Hopefully he'll get it sorted.

ferox100 said:

Its the white one with a grey band and dot

Click to expand...

Look at the blue one next to it - that's what it looked like before it was overloaded and overheated.
They are "SOD-57"

I cannot find any info on them; the only blue ones I've found are very definitely different.

As Nigel says, with enough info about the thing they are used in, it should hopefully be possible to find a compatible replacement.