Help identifying SMD Diode

[Leggyownz]

I have this diode that is reading both ways. When plugged in it gets hot and starts smoking, I suspect there is another problem within this machine but wanting to attempt to try the diode and a proper power supply first. I haven't had to do much with SMD components at this point and so I haven't had to look up the codes before. I tried looking the one on this diode up but came up empty handed on my search. Hopefully someone knows what I'm doing wrong and can explain it to me for future reference. Thanks in advance

 

[davenn]

I have this diode that is reading both ways.

I assume you are referring to D3 ?? you didn't give that info

what is the reading in each direction ?

what is written on the diode ?

it's possible that Q1 is affecting the reading
the diode will need to be removed for proper testing
and probably the same for Q1

 

[Leggyownz]

D3 gives a dead short both ways. Reading through Q1 gives completely different readings thanks to c2 and c3. The dead short only occurs across d3. I can pull it off and test it which isn't a problem but was trying to identify it first on the off chance it falls off the board and gets lost or something damages the top of it (just the rare but absolute pains that could occur)

 

[kellys_eye]

Indicative of reverse polarity applied to the device - be prepared for more faults!

 

[davenn]

D3 gives a dead short both ways. Reading through Q1 gives completely different readings thanks to c2 and c3. The dead short only occurs across d3. I can pull it off and test it which isn't a problem but was trying to identify it first on the off chance it falls off the board and gets lost or something damages the top of it (just the rare but absolute pains that could occur)

so you didn't answer my Q

WHAT is written on it ?

 

[Leggyownz]

Sorry, missed that question. So it says "407" on the first line with an emblem of some sort before that and "L Z" on the second line below it. Picture below is my drawing of what it says including the emblem.

I am definitely assuming more faults to come after this.



[Mod Note -- Image resized]