Dead Diode?

[Speedy78]

Trying to build my first laser with a S06J. Had it all wired up. it turned on for 3 seconds and then died. Its running at 450mA. Pulled it apart and hooked it directly to the power supply and as soon as you start to turn the Amp control knob the power supply clicks and the voltage goes to the max possible with zero current. Was running the diode fine when I first got it off the power supply. Is this a sign of a dead diode?

 

[DTR]

Not to say the diode was not in trouble before you powered it with the power supply but what voltage did you have the supply set to when you powered the diode? On mine you only hear that clicking on mine when the voltage goes over 8V which is way past the forward voltage of the diode.

I always suggest to first set the power supply just under the max forward voltage of the diode in this case I would start about 5.5V since you are just testing it and turn the current to zero. Then turn off the supply, short the leads together, connect the diode and turn it on. This can reduce the potential of the supply in the event of a startup spike or human error. Then you can slowly turn up the current. I suggest never adjusting the voltage knob while the diode is connected as you wont see what the voltage potential when driving the diode in constant current mode.

This is the method I use for a 445 which is the same for a 405 just with a slightly higher voltage potential.

 

[Speedy78]

originally it was around 6 when I first set it up and got it to power on. Just set it to 5.5 and turned the current knob all the way clockwise with no current flow and no laser light

 

[Blord]

The 405nm can die at 450mA. I have experienced it twice. The diode dies in between 400-500mA. My other S06J diode is now running at 400mA. I don't dare to push it higher.

 

[Speedy78]

Its just weird it died that fast. I had it running at 450mA on a bench style heat sink for like 5 minutes running some tests with no issue at 670mW. It is the first laser I'm attempting to build and the press fit heat sink in the host didn't seam very tight to me but I figured that's just how it is. Quite possible that there wasn't good contact between the diode and heat sink. Have another diode on the way and looking at possibilities to revise my plan to get better connection.