Hi ! I am new here actually my occupation is Computer science but I gathered a bit knowledge from electronics, I have a broken welder, so I thought maybe I can find a problem myself, found this diode with corroded check point, so it became my suspect
Checked it with multimeter from both sides (polarity change) and it beeped (Long Beep or 0 resistance) from both sides, I know that diodes allow only one side beep defined by diode sign ->- ,never saw this diode so I don't sure how it behaves and can I check it at all with multimeter.
Uploaded a photo with a corrosion .
Help appreciated
Thank you !
Feliks

 

MURF1560 ... mistyped as MURF1520 .
Checked again, zero resistance from both sides.

 

Diode should be tested out of circuit, lift one leg up, and test on" Diode" with multimeter, you should get 0.7V one way and open circuit the other way.

 

I know, I can't take it out, there is a heatsink on the other side, what the difference if it inside the circuit ? still it has zero resistance from both sides. It is a 600v diode