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NUBM08 decaned by accident,lets do some testing then

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hello everyone yesterday i was testing a NUBM08 diode and i accidently the can popped out while i was removing the diode from the heatsink,we all know how this diodes tend to degrade after some time if you take the can off but this weird idea and question came to my mind,what will happen if i seal the can back? :thinking:

i used some super glue to seal the can again to the diode



and after that i made a power test at 1.5A


i'll update the thread once a week with a new power test to see if the degradation will stop at some point or will continue till death.




purpose of the test and usefull info: i expect that the diode will degrade but after that im curious to see if will stop at some point,if the theory proves correct it will be awesome if some of us have lets say a deccaned diode that starts to degrade and we dont want to lose it completly yet,maybe the reseal gives some more time or save the diode from complete death.lets see :whistle:

edit,updating results:
started:1761mw
week 1:1661mw
week 2:1668mw
week 3:1737mw
week 4:1739mw
after 2 months total time:1434mw
after 5 months total time:1426mw (seems the degradation have stopped at this point)
 

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BobMc

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Very interesting test. Will be following closely. Great idea! :)
 

diachi

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IIRC the cans are filled with inert gas that helps prolong the life of the diode, could be wrong there.

Also, for future reference, superglue is a bad choice for anything optics related (can cause issues with other things too). The vapors tend to deposit on optics and cloud them.

Keep us posted! :beer:
 
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IIRC the cans are filled with inert gas that helps prolong the life of the diode, could be wrong there.

Also, for future reference, superglue is a bad choice for anything optics related (can cause issues with other things too). The vapors tend to deposit on optics and cloud them.

Keep us posted! :beer:
i have already read all the stories and posts about the nubmxx diodes and the theory about the inert gas but nobody prooved that,personally i think its just free of oxygen and the emitter does degrade with oxygen.

about the glue and optics you are right but i dont really mind for that as the purpose of testing is different.btw the focus and the splash-foggy was huge before the decan happend so np on that ;)
 
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diachi

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i have already read all the stories and posts about the nubmxx diodes and the theory about the inert gas but nobody prooved that,personally i think its just free of oxygen and the emitter does degrade with oxygen.

about the glue and optics you are right but i dont really mind for that as the purpose of testing is different.btw the focus and the splash-foggy was huge before the decan happend so np on that ;)

Dry air is pretty inert if you remove the oxygen from it. :whistle:All your left with is Nitrogen, Argon, CO2, Neon, Helium, and Methane, with trace amounts of whatever else. Only thing there that is fairly reactive is the Methane, which is a tiny fraction of the other gasses.

Anyway... :p

Okay, as long as you know about the super glue vapors. Hopefully other's see that as well. :D
 

RedCowboy

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As I understand it oxygen will break down at the point where the energy leaves the tiny p/n junction right in front of the tiny mirror surface, this break down of oxygen damages the window and reduces the output over time.

While being stored in between use there is no damage that I am aware of, it's during the time it's powered on, for me it took about 30 minutes a day in 3-5 minute runs in a heavy heat sink @ 4 amps for 6 weeks to reduce it's output to roughly half brightness, that's roughly 22 hours of runtime out of a 20K hour diode albeit overdriven, on the other hand I have a NUBM06 with it's GBall intact running through a 3X BE and it's still burning strong after many months of use at 4.5 amps.

My point is it's not the storage time but the run time when damage occours once oxygen is introduced around the tiny emitter where the energy beam is at it's tightest.

Have you seen the tiny little place where all 7 watts come out ?

This is the inside, the pin is one of the same pins that stick through the back plate where you make your connection.



---EDIT---

These 2 pics are from Astralist



 

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paul1598419

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I have a 500X video microscope that takes these kind of photos, but the depth of field stinks to high heaven. You need to be able to position it exactly where you want to photograph. Everything else is out of focus.
 

RedCowboy

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I have an inexpensive little USB scope with a thumbwheel focus, it's ok and I can cheat small things in past the guard bezel, now Astralist got some sharp pics, I don't know what he used.
 
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As I understand it oxygen will break down at the point where the energy leaves the tiny p/n junction right in front of the tiny mirror surface, this break down of oxygen damages the window and reduces the output over time.

While being stored in between use there is no damage that I am aware of, it's during the time it's powered on, for me it took about 30 minutes a day in 3-5 minute runs in a heavy heat sink @ 4 amps for 6 weeks to reduce it's output to roughly half brightness, that's roughly 22 hours of runtime out of a 20K hour diode albeit overdriven, on the other hand I have a NUBM06 with it's GBall intact running through a 3X BE and it's still burning strong after many months of use at 4.5 amps.

My point is it's not the storage time but the run time when damage occours once oxygen is introduced around the tiny emitter where the energy beam is at it's tightest.

Have you seen the tiny little place where all 7 watts come out ?

This is the inside, the pin is one of the same pins that stick through the back plate where you make your connection.



---EDIT---

These 2 pics are from Astralist



this is quiet an interesting theory about those diodes that need to be powered on to be able to degrade, i dont really know about that,does anyone tried to keep a decaned diode stored for some time?

yea dont worry i know alot already about diodes,seen tons of photos and i have already read all the post history of blue diodes since the first 1W diode that came out :wave:

so you guess it will not degrade if i only turn it on fo a power test,interesting ;)
 

Benm

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I'm not that convinced that the diode package is filled with some inert gas, since there would be little reason to do it. Even if it was just dry air in there, the volume is tiny and so is the amount of oxygen. It may oxidize the inside of the case or even something on the die, but it's just such a tiny amount i doubt this would be a problem.

One benefit of a hermetically sealed can would b to keep out any -extra- oxygen, as well as dust, moisture and all that.

I remember taking off the cans from metal bodied transistors like 2n2222's to use them as light sensing devices, which never really posed any problem unless dirt or water got in them.

Th chemistry of laser diodes IS different, but probably perfectly fine with exposure to oxygen as they also produce laser diodes without a can for practical use.
 

RA_pierce

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I agree with Ben but I'm not a materials scientist (what ever happened to pullbangdead? Wasn't he a materials scientist?) and I think the semiconductor materials used for blue diodes are different than those used for red and IR diodes which I have seen in open-can variations. I have decanned a 405 and 445 diode in the past with no issues over a year or so of use so I'm not convinced that decanning is all that bad. However, these diodes are substantially more powerful than the ones I've decanned so perhaps the high operating power results in faster degradation or other bad chemistry.

While walking to throw away some trash, I did think of a way to test the can vs. no can degradation hypothesis.
I have access to LN2 in the lab. I think it would be possible to pour some of the dense, very cold N2 vapor that floats above the liquid phase into a container with a removable lid that can be sealed. Ideally this dense gas would displace the lighter, room temperature air. Holes could be punched through the lid, through which leads could be passed then sealed (with epoxy), to which a diode could be connected to. We could decan a diode, stick it to the leads, fill the jar with N2, close and seal it. That would be our experimental group. We could do the same thing with decanned diodes in regular ol' air and a control group with diodes with cans not removed.
What do you think, guys?
 
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RedCowboy

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Just run a de-canned diode next to a can intact diode for 30 x 1 minute cycles a day and test the output at the end of each day. Both diodes must be the same, as in NUBM08, and both run at the same current in the same size heat sinks.

As the days go by the results should speak for themselves.
 

RA_pierce

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Just run a de-canned diode next to a can intact diode for 30 x 1 minute cycles a day and test the output at the end of each day. Both diodes must be the same, as in NUBM08, and both run at the same current in the same size heat sinks.

As the days go by the results should speak for themselves.
That doesn't reveal if an inert gas is used in the can but it is simpler to test longevity of canned vs. decanned.
 
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Shotgundrums

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Such fascinating tiny technology!! I'm sure with close-ups like these we could probably see more clearly what happens when diodes become zombified... maybe clues to resurrect...? Pretty cool imagery, nonetheless.
 




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