Laser dies NDB7875

So 2y ago i purchased the Nichia NDB7875 3 Element lens module and i had it all this time in the host i used it maybe 15sec in the 2y period it worked perfect today i made a decision to replace the lens call it 3E with G2 it worked perfect then i decide to burn some cardboard in the kitchen
i turned the laser on and started focusing it i got it focused perfect and after like 10sec the diode just dimmed down i was thinking its the battery's since i used protective battery's, so the mystery is what killed the diode i just tested the driver works perfect 2A on the dot so its not the driver. could it be the lens reflecting back or too close to the diode or the batteries for having protection ?

My protected batteries cut out completely. It sent me on a testing mission one time. Not sure what's up with your diode or setup.

No!!!! Did you try CPR, mouth to mouth, electro shock, lay hands on it?

So sad

a moment of silence please , :cryyy: :cryyy:

(BobMc) Lol the diode is still alive in a way just its maybe 50mW and its not blue its more green blue and it gets hot
i just ordered another module
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I thing the G2 lens may got too close to the diode and back reflection, will be back doing some test on the driver

Alien Laser said:

(BobMc) Lol the diode is still alive in a way just its maybe 50mW and its not blue its more green blue and it gets hot
i just ordered another module
-
I thing the G2 lens may got too close to the diode and back reflection, will be back doing some test on the driver

Click to expand...

50mw's sounds like she had a stroke, don't think there's any coming back from that. Pine box being built.

Talked to DTR and he said the ndb7875's are being discontinued, he managed to purchase 100 of them but that may be the last. I grabbed 2 diode/driver combos, thinking about a couple more just to have for future builds. (Just letting you know.)

Will be interested in what your testing shows about the lens getting to close to the diode. :thinking:

Sounds like it LEDed on you. It happens when these are driven harder than engineered to. Sorry it happened after such a short time, but you said it is a 2 year old build. You may never know exactly what caused this failure. I didn't realized they were discontinuing these diodes. Hope that isn't true. I don't have any in my current stock, but don't have a need for any either.

It happens, but it seems to coincide with the lens change very sharply in this case.

One option that is possible is that while changing lenses some dust made it's way into the unit, and perhaps it ended up on the laser diode.

It may be worth verifying that by inspecting the diode, just to get confirmation it was not some reflection from the lens that killed it. The latter is certainly possible when driving diodes far over manufacturer rated power levels.

Those diodes are in a can and should be highly unlikely to allow anything onto the diode emitter.

(Benm) we have like no dust in the house in this room i use 2 air purifier + ion

That does not make your house a cleanroom

Dust is everywhere, visible or not. Also, you yourself are a pretty decent source of dust - people may not like this idea but a significant portion of household dust comes from your body in the form of shedded flakes of skin etc. Clothing also sheds quite a bit of dust when just moving around, it wears down for a reason...

As for the effects on a laser with a window - dust could still kill that by baking onto the window, either distorting the ouput pattern or even causing a reflection back into the diode killing it that way.

In the intended application the laser diode is quite well protected from dust by the projector housing and such. Diodes for optical drives can even be windowless because they are inside a sealed sled, and optics + lens pointing towards the disc shield it. You might get dirt on that lens pointing at the disc, but optical power density there is not so high it would irreversibly bake on and you could clear the lens.

in this room i used many open can diodes and never had an issue, i thing the G2 lens got too close to the diode or its overdrive the driver is set at 2.4A
the air in the house is so clean since all air is going threw 9 HEPA filters and back in the house its a central air purification each room got different settings
once i use fog i have to shut it off in this room once am done i turn it on the sensor detects the fog clean the room like in 5/10sec what i did i purchased 3 more air cleaners lol

Did you decan this diode? It comes with a can and there is no reason to remove it. I have one from more than two years ago that is still going strong.

no its still has the can on, i gave 1 to my friend 2y+ ago and his is still laser is ok , what lens are you using

It's difficult to remember, but it's either a G9 or a G2. I used canned air to remove any dust that might accumulate there, even though it is sealed against this happening.