- Dec 18, 2013
I have built around 50 of these @ 700mA with the microboost without issues.
Please accept my condolences during your time of loss
Thanks for sharing it, hopefully the insight gained will help future builds.
I think I used a flexdrive in my build with this diode. There is a thread on it somewhere. Not sure why I chose that drive, must have made sense to me at the time. I remember someone commenting it may not have been the best choice in drives.
I know I set it to .666ma, I'm getting 1w output and it still lives. A few days ago I was shooting it through a diffraction grating taking pictures, it does seem to have a long run time with out overheating.
I'm thinking this was just too high a current for this particular diode. Might have been fine with another diode.
Hopefully we get some good drive info from this.
That is not a bad idea to have one scoped to see where they are with these diodes. I think I will shoot one over to Lazeerer and see what he comes up with.
(Edit) Summary of thread: I set the current too high (765 mA), but the diode was fine until the battery voltage sagged and put the flexdrive out of it's specs range, and that is the believed cause of death. Even with initial input voltage of 4.2V, the flex was technically already out of it's range at that current, but it did not kill the diode until a good 20 min of battery drain. (it was a 3100 mAh battery, so at an estimated 4.0 V, maybe??). So, hopefully we will get some scope data on this driver and confirm this theory.
The purpose of this thread is to isolate the cause of death and hopefully add to the limited information available on this diode. I welcome any thoughts and comments that might provide helpful insight.
*There is not much to see other than sinner's spectacular handiwork, so I will not post pics unless necessary.
- MS-SSW-III host (check it out here)
- Flexdrive set to 750 mA
- 1x18650 orbtronic cell + blank 18650
- G-2 lens
- DTR silicon wire
So, I recently got this diode from another member here (who got it from DTR) because I have been wanting a 405nm build for a while. Unfortunately, the diode died before I could even add it to my sig.
The sinner host seemed great for extended duty cycles, and (while it worked, it never even got warm).
The build part was pretty standard, just soldering some wires (slowly, I admit). I stuck the flexdrive in the pill, heatsinked with copper wire and protected by electrical tape- thankfully I just used tape to secure the driver in the pill. All, assembled, it worked great. Nice, visible 405nm beam. Really great divergence, too, I was surprised. I used it sparingly at first, keeping cycles to ~1 minute on/off (I had to, it burned everything it touched).
BUT, then I wanted to get it warm to see realistically what the duty cycle should be. I timed it, and 3 minutes 15 seconds into the test, the diode suddenly stopped lasing. No warning, just LED'd (I assume this is the correct term). I immediately clicked the clicky switch off.
When I turned it back on, I saw that the diode was still emitting a faint light, but the divergence was terrible- at 10 yards, the focused spot was about the size of printer paper and barely visible in complete darkness.
I opened up the pill and lowered the current by ~70 mA. Same result. I haven't done anything more to it since then, but soon I will disassemble. But first, I need to clear up some issues.
What I suspect could be the problem:
I have two theories, and I do not think the diode is to blame.
Either a). I soldered the driver poorly, which caused the output to gradually increase, which destroyed the diode from current overload.
Supporting Evidence: I noticed while setting the current that this was in fact occurring. The current would start out consistently (I tested several times) at 765 mA and VERY slowly it would climb. I barely noticed- I thought it was just slight fluctuation. But then I conducted a longer test. After 7-8 minutes at least of constant run, the current came up to 784 mA when I stopped, again, after 8 minutes of constant run because the test load was getting pretty warm.
Refuting evidence: The diode died very suddenly, without any signs of dimming or heat (when I felt the host immediately after, it was barely warm). If it was current overload, one would expect dimming at least. Although my soldering is not professional by any means, it's not exactly easy to mess up assuming you're careful and patient, and my job looked solid- I was very thorough. Also, the current ramp-up was extremely slow, and the power graph on DTR's site showed the peak (power) at around or above 850 mA.
Or b). the host has a weak contact point in the tailcap, which caused a current inrush every time the clicky was pressed, which eventually caused a spike that killed it immediately.
Supporting Evidence: While I was setting the current, every once in a while, I would click it and the multimeter would still read zero. I had to click it again (twice, to be "on"). Then, with the diode connected, the problem persisted. At points, it seems I had to click it several times to get the mechanism in the right spot. This was pretty annoying, but I did not think much of it. The clicky is metal, and the spring inside it *feels* (I have not opened the clicky) like it is not secure, as in when the host moves, the metal button rattles. The sudden manner of death seems to fit this(?). I have read multiple accounts of bad clicky switches and also that not having secure contact points can kill diodes.
Refuting evidence: It's a sinner host . And it worked for a little bit. I can't think of anything right now.
Anyway, thanks for reading. Please share any thoughts, ask questions, whatever. If nothing else, I want to know if I can still use the host, driver, or both as is, or if I need a new tailcap, maybe. Cuz, well, it sucks to lose a diode, and doubly so to lose a diode, driver, and host together. I also hope that when I get the money, I can buy a new sled, get the diode from that, buy a diode press, extract the old diode, and press in the new one (if I trust myself to do that much).
Hopefully the information in this thread will add to the info available for this diode, though I doubt that the diode itself was to blame, given its performance with others.