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FrozenGate by Avery

505nm and 480nm diode RESULTS

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Meh yea that is too bad... my 505 is still in the esd bag. Was hoping these were a Lil stronger... I had a few build ideas..
 
Podo said:
We bought two 480nm diodes and two 505nm(SB147EC91) diodes off LPF but the results are quite disappointing.

The first 480nm diode runs smoothly at 200ma in our guardian housing, we will run it continuously for a week to see how's it holding up.

Yet the second one led'ed the first time we put it into test at 200ma, literally the first second, no flash, super weird.

And there is no stop of that, the first 505nm ran a good ten seconds at 150ma before gone to led mode(in the challenger housing, copper heatsink) and the second one faced the same fate as the second 480nm diode.

Maybe we received a bad batch...but the results are very different from we saw in the thread...

Well, at least we have some pictures of the 100mw 480nm guardian:
View attachment 56678 View attachment 56679View attachment 56680 View attachment 56682
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Very strange, indeed. I had 14 of these diodes to test. I pressed all but two of them and only had one of the 473nm diodes LED right out of the package at minimum current. No flash, or lasing....just LED at 50 mA. The rest that were pressed survived being pushed to 300 mA up to 350 mA for some. Didn't lose a single green diode. I have a driver coming that will drive my 477nm diode at 350 mA. That is still my plan, but I am getting a bit nervous hearing about all these failures. Huh. I guess I'll see what I feel like when the driver gets here.
 
Well, diode life is hard to predict, if these are prototypes or something, which they probably are preliminary of some kind, then they probably don't meet a normal quality control. Their life will be a function of current and case temp. These will likely be designed to be tec cooled and ran at 25C. Passive cooling cannot keep them cool at an appropriate temperature. as current increases lifetime decreases exponentially, much like an Argon tube does, and just because it can survive at that current for a while, doesn't mean it isn't still damaging the diode facet and other things you cant see. Not counting any flaws in the crystal/semiconductors as it is that are probably present. I always press mine with thermal paste gently, and then grease them into a cooled heat sink, and run them for maybe only a few seconds at a time. Heat takes time to transfer, and if the casing is not even warm, that doesn't mean the diode isn't! you can't forget you're cooling something microscopic essentially...

Also, not that I wish to be insulting and with all respect...but frankly I don't know why people can't just accept diodes like these for their specs and quit while they're ahead frankly...years ago even going 1mA above rated on these would've been blasphemous as can be! they'd have been laughed right off the forum! These aren't big MM GaN diodes like the 445s made for laser shows! They're scientific diodes, and actually made with quality in mind. They will be very intolerant of abuse, and it's showing.
 
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ZRaffleticket said:
Ouch. Things are not looking good for these diodes...
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Well if they weren't Over driven they would not be popping just saying :tinfoil:

EDIT:
ultimatekaiser said:
Also, not that I wish to be insulting and with all respect...but frankly I don't know why people can't just accept diodes like these for their specs and quit while they're ahead frankly...years ago even going 1mA above rated on these would've been blasphemous as can be! they'd have been laughed right off the forum! These aren't big MM GaN diodes like the 445s made for laser shows! They're scientific diodes, and actually made with quality in mind. They will be very intolerant of abuse, and it's showing.
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^^^^^What he said ^^^^^​
 
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You know we can all speculate about why one diode survived while another did not...... but, in the end, it's still just speculation. I can't say why some other diode failed and I could come up with a theory that made sense on its face, but it still would only be a wild guess. I am going to give this some more thought. Might run mine on my PS for a period of time to see what it is doing spectral-ly. Then I will make a decision.
 
Generally facet damage is the leading cause of death. I'm not singling anyone out.

Generally a lot of lasers in an industrial standpoint are cooled before they are even turned on. And they are usually ran at or just under rated current. The facet can only be cooled internally so fast, regardless of whatever external cooling used. Single mode diodes are not designed to take punishment like the big MM ones. They are generally made to be in a closely controlled environment.
 
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ultimatekaiser said:
Also, not that I wish to be insulting and with all respect...but frankly I don't know why people can't just accept diodes like these for their specs and quit while they're ahead frankly...years ago even going 1mA above rated on these would've been blasphemous as can be! they'd have been laughed right off the forum! These aren't big MM GaN diodes like the 445s made for laser shows! They're scientific diodes, and actually made with quality in mind. They will be very intolerant of abuse, and it's showing.
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I think that's a VERY good point UK made here. I understand wanting to overdrive the 473 diodes in order to try and get as close to 488 as possible, but what is the point of over driving the 505 diodes? Isn't all you are doing is simply losing potential lifetime on the diode, and pushing the wavelength closer to 515-520?

-Alex
 
My feeling is its either these really are preliminary diodes that the manufacturer couldnt stand behind, with quality, life expectancy and warranty....or they are extremely sensitive to the Boost circuitry on startup with above 120mA current settings.

I've been running a 505 (SB147EC91) diode @ 150mA-200mA on my Benchtop PS (slow increase in voltage till the limit of 150 or 200mA is reached, and then held there for 2-5mins) No Problems so far!
and
Running the 473-480nm Diode @ 250mA, same setup on the Benchtop PS, soft start till the limit of 250mA is reached. Same, no problems so far!
 

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Sorry to hear Podo,
Lots of mixed results from different member's atm. I'd be extra cautious running these Diodes at above rated currents using Boost circuitry, seams to be one thing i feel might be in common with results so far, perhaps.

Like Paul said..

paul1598419 said:
You know we can all speculate about why one diode survived while another did not...... but, in the end, it's still just speculation
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Hap said:
^Those are some nice pictures :)

-Alex
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Thanks Alex, took awhile to get these shots so hope the members enjoy them :beer:
 
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Love those beam shots, jrnpop. I have a driver coming for my 477nm diode that's set for 350 mA. But, with all the failures and people agonizing over the drive current, I'm starting to get anxious about this current and might hold off and drive it at 275 mA. Funny how ones mind works with all the contradictory information out there. IDK?!
 
There are never any problems on a benchtop PS it's when it's turned on and of in a handheld were the problem is, i don't think the soft start on some drivers is soft enough, if we had a 3 second soft start they should be fine in a hand held even at double current,

Just like the adjustable NDB 7675 I have in a handheld when you slowly increase the current to 2.8a. The colour changes dramatically in front of your eyes and even more when warmed up. If only we had a blackbuck M8 with low enough current!

https://youtu.be/GbwFSMTl8ck
 
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Well tomorrow's the day I get my 480 built provided I don't screw anything up. I'll take pics of that, then swap out for the 474.5 and start seeing if it can handle a lot of use... fingers crossed.

Also the camera doesn't pick up on the color shift too well on that.. but is really cool seeing the external pot
 
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Can't wait Zach,
I just got this diode seted perfectly, because I do my heatsinked pressed I didn't use the alloy back to guide my diode because it didn't fit, luckily it wasn't pressed all the way chucked it on the lathe brought it down a little so I was able to screw it on the back of the copper module to guide it straight even though wires were already soldered, dangerous operation but I felt it press a little more and checked the can perfect very happy about that,
Nothing worse than a beam coming out on an angle,

I did a little testing again and 200ma just isn't enough output I'm going with 250ma this diode isn't as nice colour as the other so hopefully it's more efficient and is happy! I have one more back up on the way at 477. Thanks Zach!

https://youtu.be/SGcsNtjrF0o
 
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