Help identifying ceramic bead diode?

This appears to be a diode, and tests out as one, if you look closely at the photo (diode shown with yellow arrow pointing to it), you will see a dull grey stripe near the black end of the diode (between the blue dot and black area).

The diode I am trying to identify the type and parameters of, is identical to this one, except that the grey stripe is black. (it shattered after a short) - It has the same 4 blue dots in the white area - but like the one photographed, no numbers or letters on it. So identical to photo, except black stripe rather than faint grey stripe, near black end, and 4 blue dots in the white area. Found on Nissan engine computer.

I am not able to tell by the photo what the specifications might be. Is there any type of part number?

Hi cowboy,

Pretty hard to say with any certainty without more info. The only thing I will note is that it is next to, and appears to be connected to, the Vcc pin of the TD62706 six-channel current driver, which is rated for up to 60V. Therefore, I would expect the diode to be rated for at least that high a voltage, and probably substantially more.

Assuming it is meant to protect it from inductive kick-back from whatever those channels are driving, it probably doesn’t need to be particularly fast or rated for more than an amp or two.

If you can’t find out any more info from a schematic or such, and you have to try something, chances are something like the 1N5406RLG, rated for 3A and 600V would be more than sufficient.

However, this is only speculation based on what I see, and no guarantee that it will actually work.

OK, these all look similar to it, but which one, and do I want avalanche type or no?

based on measurements with a digital caliper, pretty sure it is SOD-64 package

The only doide in your search that says it is standard diode instead of avalanche diode has a JEDEC part number for an avalanche diode (it’s a 1993 data sheet and IIRC the term avalanche diode wasn’t used a lot last century on US data sheets).

So I think you are dealing with an avalanche diode used for surge protection that died protecting the other circuitry during the short circuit.

Based on those guesses, I’d first try the lowest reverse voltage, 100V, avalanche diode in your list. This would also align with @David_1528 figuring out that the protected circuit is rated for 60V operation.

If the diode keeps blowing out during normal operation I’d then try a higher voltage version.

Thank you for the great answer, this was more thought out than any other answer I got elsewhere on the Internet, including inquiries on the largest electronics forums. I’m going with that diode you mentioned, as I believe that reverse polarity protection (some goofball hooking up his jump box to the dead car battery with the polarity accidentally reversed) was exactly the scenario the ECU designers at Hitachi were trying to protect the ECU from.

Have a look at this last photo, this is the actual diode that shorted, and then cracked when touched - does it’s location change anything?

No, that location doesn’t alter my guesses.