Is my diode dead?

[MTG18]

While building a flashlight mod laser I hot glued a diode in place to prevent the LD terminals from breaking/twisting off. Would the heat from hot glue be enough to kill an almost brand new diode? I am testing the laser diode + ddl driver and am reading around 6.3 volts to the diode terminals (power source is approx. 6.5 V). If the LD is the load shouldn't the LM317 be taking 3V? Leaving me with around 3V to the LD. I am getting no response from the LD and think it may be dead : ( is their anyway to check that a LD has been killed? Wouldn't it still emit some light even if it was dead? Any suggestions as to what my problem might be would be greatly appreciated.

Thanks!

 

[clwatkins10]

hot glue shouldnt have killed it... unless you used a ton all over the module.... :-?

 

[MTG18]

I did almost entirely surround the diode and module with hot glue, but not really all at once. Im sure it did get the module and diode quite hot, but only for maybe a minute or so.

 

[clwatkins10]

hmmm. sounds iffy, did it cool completely between applications?, and what kind of hot glue gun, a standard "mini" or a big industrial one (as in costing more than $20)

 

[chido]

I don't think the hot glue gun killed it, especially if the diode was already press fitted in the module. Did you power the circuit before soldering the LD, if so, did you short out the capacitor before soldering the LD?
A dead LD will still output some light, but it'll not get very bright. Here's a diagram of how to properly test your circuit without risking the diode:

 

[gn0stik]

This sounds to me more like a  problem with your driver. Did u test it before you started? Turning the pot etc to make sure it dims. Then there's the test procedures posted above which are crucial. This tells you if the driver is responding to load correctly, and delivers the correct voltage and current. However, this is not to say that your LD is not dead now. Driving it with a faulty board will kill an LD. Not that I've ever done that.  :-[ ... a couple times ....

 

[MTG18]

hmmm. sounds iffy, did it cool completely between applications?, and what kind of hot glue gun, a standard "mini" or a big industrial one (as in costing more than $20)

It did cool between applications. I first just surrounded the module, then let it cool. Then glued over the actual diode to prevent the terminals from breaking or being twisted off.

I did not solder the diode to the terminals but I have been very careful about shorting out the CAP before connecting the diode.

I know the driver is working ok because I had it working but was having problems with a wire touching the negative aluminum body and thus completing the circuit. So I took apart and made it more durable. THis is when I hot glued the diode in.

When measuring the voltage to the LD terminals I am reading the battery voltage ( ~ 6.4 V). If the circuit recognized the load (LD) wouldn't I be reading the voltage after the LM317 has dropped 3V or so? I am also not seeing any light at all from the diode.

Prior to hot gluing the diode in, I noticed the positive LD terminal was free to rotate in its hole, although it was still definitely attached.
Perhaps this terminal is no longer internally connected.

Any other suggestions?

Thanks so much for all your help

 

[chido]

Prior to hot gluing the diode in, I noticed the positive LD terminal was free to rotate in its hole, although it was still definitely attached.  
Perhaps this terminal is no longer internally connected.

If it rotates then the diode is dead, the anode got disconnected from the little golden wire inside.