ok, thanks… since the light was fully assembled, it would have had its best possible thermal path.
it is debatable whether the H10 contributed to the overheating… it is implicated in burning LEDs on the TS10.
Im skeptical that the burned LED has no glass… please verify
could you please look carefully at the burned LED, from various side angles, while facing a light source, such as a window or other light source, to verify whether there is any glass over the phosphor on the burned LED
you need to look for reflected light. It is the same process as looking at the reflected light on a glass lens, you have to position it just right so you can see the reflection
Thank you. I’ll take a closer look when I get home from work today. If that ends up being the case, would I just need to purchase one of these from Convoy?
In my opinion, the telltale sign of overvoltage is the 15 seconds of transitioning to blue…I’ve done it with many bare emitters, ranging from 5mm to xpl. Overcurrent would just make it superbright before poofing.
If you have a DMM, you might want to check the circuit for its electrical properties before dropping a fresh LED in there…or order a few in case something goes wrong again
What tools were used and did you do any cleaning and again what tools and or materials for cleaning?
Did the dome come off in one piece or did you have to go back and keep scraping pieces? Was the white spacer removed at any time?
The only thing I used was the end of a q-tip with the cotton head removed, and a 70% Isopropyl Alcohol wipe. The dome came off in one piece, besides a little of the glue residue which eventually came off with the q-tip and when dabbed/wiped with the alcohol wipe.
I actually forgot, the white spacer did come off the first time I unscrewed the bezel to take a look at the emitter for dedoming. It fell right out. Does it look like I may have reinstalled it incorrectly?
The transition to blue signals phosphor saturation (power density beyond what it can handle), not overvolting. Overvolting can cause phosphor saturation, but is not the only cause. Damaged/delaminated phosphor can do the same thing, which is the reason why so many LED streetlights are turning purple. I’ve reflowed a few 519A’s too hot for too long, and as a result the blue shift happens even at 500mA of drive current.
The heat-and-push method of dedoming is not reliable, and there have been documented failures once in a while. It’s not hard to imagine that perhaps the bonding force (or vaccum) between the dome and glass can pull hard enough on the glass/phosphor to cause delamination. My preferred method is slicing until the glass is reached, and have a failure rate of 0 out of 20 or so emitters. Also the result is much cleaner, no silicone fragments left.
There IS a possibility that using that centering ring upside down, failed to press the mcpcb firmly against the shelf, thereby failing to remove heat, that burned the LED.
yes you need a new LED, and buying it preinstalled on the mcpcb is a good idea, as it saves you from needing to learn how to reflow the LED, but not “just”
the process to install that mcpcb requires using some products you would need to buy
Thermal Paste that goes on the shelf under the mcpcb
Solder Paste that goes on the solder joints that connect the wires to the mcpcb
soldering iron, properly coated with correct solder type
tweezers to hold the end of the wires, without crushing the insulation.
this photo album demonstrates the processes involved in removing and reinstalling an mcpcb with LED
it would be cheaper to buy a new light, than the cost of supplies and equipment to do the repair
Seriously, thanks a lot guys. Being a member of multiple knife related forums, I’ve seen some brutal replies to new members with questions/problems. Everyone starts somewhere, so I really appreciate all of your patience and replies in helping me understand and hopefully learn from my mistakes.
The white(which is black sometimes) thingy which I normally call a gasket or centering ring may have applied some horizontal pressure to the LED or something and damaged it.
I think anything we come up with is sorta a guess at this point.
Bottom line is, if you replace the LED, the light would likely be fine.
I know most of the things have alredy been addressed here, but I wanted to give my input!
In the image below, do you have a “glow in the dark” or plastic ring (#1) inside the head of the flashlight?
If so, does it mean that you were not using a reflector when you turned the light ON?
If that is the case - you were not using the reflector - it probably means (as @jon_slider said) that the heat dissipation path was not good and the led board (PCB or MCPCB) was not in contact with the flashlight shelf, therefore putting more “stress” on the LED making it burn. (I’ve done it too, don’t feel bad)
If this was the case (not using a reflector and instead using a GITD/plastic ring that does not press the LED board against the shelf) , it also means that, independently of using a dedomed or domed LED, you need to rethink your configuration, since you need something to press the PCB against the shelf to make a good heat dissipation path.
Or, maybe you need a less powerfull battery (ex: not high drain). BTW, which battery did you use? Was it the Vapcell H10? If so, part of the buring is also explained…
Also in the image below, isn’t there a piece of the LED structure (black dot) missing in the #2 ? If so, maybe it had some influence in why it got burnt. But of this I am not so sure. However, it misses in the same part where the brown spot is located…
based on the damage shown to the corner of the LED base, that MascaratumB pointed out, my guess is the bumps on the inverted centering ring, might have damaged the LED phosphor by pressing against the glass cover.
In any case, I respect that your questions are focused on learning how to avoid the problem in the future.
at this stage, my opinion is the damage was not caused by dedoming. The likely cause seems to be the upside down centering ring. Since you now know that, Im sure you will not have that problem again.
I suggest you just buy a new light. And maybe gift the damaged one to someone who has the tools and skills to fix it. For example, if you list something else for sale, the damaged light could be included as a bonus.
This is a misunderstanding, you are not supposed to remove that. Removing it will destroy the LED.
You just push off the silicon dome, clean the LED and done.
Much better is to slice the emitter in layers with a razor blade. You get to decide the amount of CCT reduction or tint change, and most importantly, you don’t exert tremendous forces on the phosphor-die interface.
I suspect most or all of the videos instructed you to push the dome off from the side at a 90° angle. This is not easy with a q-tip when the mcpcb is still mounted in the flashlight.
I would contend it’s darn near impossible without other tools.
My best guess is that the downward Force that was applied damaged the LED.
It’s probably not relevant but I’d like to see a better zoomed in picture without the spacer in place. Also what does the other side of that spacer look like now?
