How to identify diode specs and part number without markings using multimeter and image

Hi, I have a board with problem. I need to know a specification of a diode which is present in the board it doesn't mention any part number. But i tested the diode with multimeter,there is no response.How to identified the part number of the diode.Here i attached the image of the component.Please anyone find it and give me a feedback.

Probably a small signal silicon diode. More details would help, how old is the board. If you don't have a schematic of any sort, then you need to look at the circuitry around the diode (draw up a rough schematic from the pcb layout if possible), and try and understand what its function is. Knowing that, a substitution should be straight forward,
cheers,
Richard

Hi there,

That does look like an epitaxial planar switching diode.
http://p.globalsources.com/IMAGES/PDT/B100129...-Silicon-Epitaxial-Planar-Switching-Diode.jpg

but diodes usually have a mark for the cathode that
can't be easily erased.

Are you positive it is a diode? If it has no response with
the diode test of the multimeter, i think it can either be a broken diode
or a busted 0 ohm resistor [never seen one with that transparent insulation].

Anyway, pictures of the board may help too.
Based on the questions I've read here in the forums, my best guess is
that diode most likely came from a boost regulator circuit / an AM demodulator circuit / or a full/half wave rectifier circuit.

Regards,
Justin

The diode seems to have thick leads.

It could also be a 0.5W zener diode. However since it is failing the diode test, its hard to say what it actually is. As others said, a schematic or photo of the board area around it might clue us in.

Hi Santhoshkumar Damodaran,

I think it is a 1 watt zener diode the leads of the diode are thick.
It must have gone open usually zener diode goes short in the worst condition
the junction barrier must have burned and got opened that is the reason why it is not
showing in the multi meter . trace both ends of the pcb track where the diode was fixed
the cathode usually will be connected to the positive supply with a series resistor check any cap +
terminal coming on the same track if so see the voltage rating of the cap, the voltage
on that line will be lesser than voltage rating of the cap trace the track to find any
voltage mentioned on the same track if so the zener diode will be of the same voltage rating
and go for a 1 watt type. usually you can see a resistor in series with the zener diode.the anode
of the zener diode goes to the negative supply usually gnd. before replacing the zener
check for any short or defective component which will come in the same track.

Pl review my rating,



Regards
V.Sambath kumar.