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FrozenGate by Avery

PHR-803T batch testing.. Windowless 803Ts?

IgorT.
I love your tenacity.

Hope you don't have skin cancer from the rays 8-)
 





daguin said:
All of mine are holding steady.  I am through with the "testing" phase, so they only get checked once a day now, but they had at least 10 burns a day before that.  Curiouser and curiouser . . . . .
Click to expand...

Yeah, as i said, it might have something to do with the total optical flux at the die... Remember, the three diodes under testing, from which two died where the three most efficient diodes out of 23.. The two most efficient ones are dead, the third is still alive.

After "losing" 2mW i almost wanted to lower the current in the third freak, but i just measured it again, and it's at 160mW.. That's why i said i want to repeat the test in the evening.. The temperature is lower now.

So the power went back up a little, even tho i put it through a lot of use today.


So i'm just gonna leave it at 170mA untill it either dies or survives and keeps on keeping on. :) Let's hope for the best..


I'm making some drivers now, so i have not gotten around to hooking up the broken leg diode permanently to 160mA (no lens)..

But one of the drivers is meant just for this diode, so the 160mA durability test starts tomorrow. ;)


I'll figure this thing out eventually..


I also got some more diodes, and will test them and add the results to the batch testing list.
 
Added some measurements for 6 more diodes....



Oh, and the third best diode is still doing fine at 161mW after a plastic lens.. It's not degrading yet.
I think i also figured out it's actual total optical output.. It's doing 200mW!
This means the other freaks were doing even more! No wonder they couldn't take it. It was simply too much optical power. It's above their pulsed ratings!

So a weaker diode might be able to survive the same current or more without a problem, as long as the optical output is not above 200mW.
Better yet, the optical output + reflections back on the die should not be above 200mW...
 
Hmm so this would defenitly be nice once you get the lenses and test those same diodes and pointers on the new lenses. You won't have to worry about reflection and will make the die's last longer.
 
Yeah, i delayed the long term high current test just for this reason. But i'm starting it tomorrow! ;)

Otherwise, my third and last freak diode died at 169mA today.. :( I thought it will be fine, as it was not doing over 200mW.. But guess what. My meter was wrong. It WAS doing over 200mW (no lens)! So the total optical flux on the die was higher than i thought..

So, an average diode can survive a higher current, as long as the power is not above a certain limit.. But since these three were freaks they killed themselves with too much power.


The third freak was the weakest of the three, so it lasted the longest. I even had it on for 20 minutes at a time several times, and again last night. But as i said, i noticed some small power loss before that, and this morning, when it was cold, and the power was at it's highest, it just died at powerup.
 
I updated all the measurements on page 1 with some new findings.. My meter was showing too little.

Now i finally understand why my freak diodes all died. Every single one of them was pushed well above 200mW before optics! :o One was doing 228mW before a plastic lens and 190mW after it! Optical flux at the die was 228 + x% reflections!


I was starting to get worried, but this is beyond their pulsed ratings. Had i known this before, i would just have lowered them to 200mW from the start.. ::)

Now i need to do that with another one. But this time with <0.5% reflections! ;)
 
I cut the can open on my PHR and ran it at 170mA for a while. Got it turned down to 150 now; don't have anything to measure the output with, but it burns leather and plastics at 15+ feet! :o
 
I need to get me a can opener.. The increase is a considerable percentage if i remember correctly..

This would allow getting a certain power at a lower current, and with a custom lens, 200mW might be possible without the diode dying after a week..

Definitelly worth trying..


On one hand i would also like to open-can the 6x diode i have on the way from Gooey_Gus, but then again, that is a precious diode i want protected... Sometimes shreads of plastic get created while focusing, and if such a shread falls on the window it's easy to remove. But what if it falls on the laser die and melts in place?

With a PHR i would be willing to risk it, but with a 6x... :-/
 
IgorT said:
I need to get me a can opener.. The increase is a considerable percentage if i remember correctly..

This would allow getting a certain power at a lower current, and with a custom lens, 200mW might be possible without the diode dying after a week..

Definitelly worth trying..


On one hand i would also like to open-can the 6x diode i have on the way from Gooey_Gus, but then again, that is a precious diode i want protected... Sometimes shreads of plastic get created while focusing, and if such a shread falls on the window it's easy to remove. But what if it falls on the laser die and melts in place?

With a PHR i would be willing to risk it, but with a 6x...  :-/
Click to expand...

I wouldn't feel right taking the can off of it :-[

They just get really really fragile and die easier without the can.
 
Yeah, i know... So you didn't open can any 6x yet, or were those the ones to die?

Also, what was the difference in percentage you found with the PHRs? I forgot...


P.S. Did you post my 6x? ;)
 
Yeah, it was posted a while ago.. But don't remember which section....


I think it was called "PHR-803T other diode", or something like that...
 
I tested 32 more diodes last week.


I used the same testing procedure as last time. A modified module, that allows taking the diode out again. A clip presses the diode into the module and holds it in place.
The driver is set to drive the diode at 109mA. The driver has a bypass resistor in parallel with the caps, to protect the diodes from cap-zapping them, and make the testing quicker and safe. 109mA is the current AFTER the resistor - the current through the diode..
I leave the original PCB on the diode and power it through the flat cable. Otherwise i would have to solder to the diode, which would warm it up and slow down the testing, as i would have to wait for them to cool down again, or the measurements would be influenced - the powers would read lower..


Here are the powers i got..

@109mA  @125mA (unless mentioned otherwise)
Weak diodes:
-  75mW
-  76mW
-  78mW
-  80mW
-  80mW
-  81mW
-  82mW
-  83mW
-  83mW
-  84mW  - 111mW

Normal diodes:
- 86mW  - 110mW
- 86mW
- 88mW  - 117mW
- 89mW  - 119mW (@143mA)
- 89mW  - 128mW (@143mA)
- 90mW  - 136mW (@143mA)
- 90mW  - 137mW (@143mA)
- 93mW  - 120mW
- 93mW  - 116mW
- 93mW  - 121mW
- 94mW

High efficiency diodes:
- 96mW
- 96mW
- 96mW
- 97mW
- 97mW
- 98mW
- 98mW
- 100mW
- 100mW
- 101mW
- 103mW  - 166mW (@160mA - climbs to 177mW as it warms up  :-?) EDIT: Stabilised at 176mW


The final powers at the full current will be added as i test them.



The powers are in this order, because i already sorted the diodes into groups.

The powers shown here are calculated to show the same as a Kenometer would show (7% more). On my meter, the groups are actually 70-80mW for "Weak", 80-90mW for "Normal" and 90-100mW for "High efficiency".



At this point i tested 61 diodes, so it's becoming a good statistical sample.
The average of the last batch of 32 is 89.8mW @ 109mA..

I will calculate the old average and the combined average later.


EDIT: Updated the list with higher current powers.
 
Just to simplify the statement --

With an input current of 109mA, the milliwatt output of different diodes removed from PHR803T sleds vary in a range of 28mW (75mW - 103mW). That is about a 27% variability.

Sorry folks. No mA to mW formula for these babies :(

It also implies that there is no way of knowing what a particular 803T based laser is putting out without a power meter.

Peace,
dave
 
Yeah.. The power at 109mA is 90 +- 15mW approximatelly.


Otherwise, i kinda have a feeling the powers were more evenly distributed this time.
I think i got more of the normal ones last time, and not as many weak ones and even less of the really good ones.
 
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