Can anybody identify this SMD diode?

[777funk]

There are two diodes here and one was reading a voltage drop of 0.005V both ways. So it's no good.

But the problem is, I can't identify it since it's SMD and I'm not at all familiar with SMD diode markings. The good one measures somewhere around 0.2V forward voltage and of course OL in reverse.

I'm pretty sure (not 100%) this is in the 48V phantom power supply.

Probably not smart of me to have made an uneducated guess, but I tried a 1N4007 in this spot and it burned up pretty quick. Maybe the diode was wrong (of course it was, going by the forward voltage drop) or maybe that whatever killed the original diode is still dangerous to the new unit.

Open to any guesses at what the diode could be and thanks in advance!!

EDIT: Maybe Shottky?? EDIT again... I feel pretty dumb in this case. A silicon diode can't handle the fast switching frequency of the boost converter most likely feeding this thing. So it must be a shottky. Assuming that this is the phantom power circuit that this is a part of (unfortunately, I have no schematic).

 

[Khron]

I'm pretty sure (not 100%) this is in the 48V phantom power supply.

Haven't bothered looking through my teardown of a Profire 2626, i guess? Or even followed (with the continuity tester on your meter) where that supply rail ends up? Test points for all the supply rails are pretty clearly marked, if memory serves.

I feel pretty dumb in this case. A silicon diode can't handle the fast switching frequency of the boost converter most likely feeding this thing. So it must be a shottky. Assuming that this is the phantom power circuit that this is a part of

Well, ultrafast diodes are also "silicon", without being Schottky, so...

 

[777funk]

I have checked voltages and the unit works (minus the blown out diode), but no phantom power. I don't think your teardown shows much detail on the phantom power end of things.

I just measured at TP940 for phantom (board is marked 52V at this test point) and it measures 18V which is what I'm getting at the diode below the missing burned out diode. So I do believe those two diodes I pictured are part of the Phantom supply. No idea how it works other than I'd think it has to be a boost converter. I think I have some Schottky diodes but no idea what voltage and current rating this would need to be. Condenser mics use a max of 10mA and there are 8 inputs so I'd guess around 100mA min would be good and phantom is 50V approx so maybe a 60V rated diode.

 

[Khron]

No idea how it works other than I'd think it has to be a boost converter.

No need, probably just an extra winding on that flyback transformer.

I can't identify it since it's SMD and I'm not at all familiar with SMD diode markings.

Fortunately we have Google nowadays...

https://www.s-manuals.com/smd/sf

Going by the package, it's most likely the SS0540 - 500mA 40V Schottky, but I'm reasonably sure they're both in series (otherwise they would be severely underrated). Any similarly (or higher) rated Schottkys should do, though.

I just measured at TP940 for phantom (board is marked 52V at this test point) and it measures 18V which is what I'm getting at the diode below the missing burned out diode.

Might it though be some voltage doubler arrangement, including those green electrolytics, though? That might explain SOME voltage making it through...