What is that dark spot? Is it possible a speck of dirt fell onto the LED and baked itself at high temp? If so, can this be cleaned? What's the best way to clean it?
Thanks!
Lots of cheap smd leds (2835 etc) have similar spots. In my suppose this is manufacuring mark that shows leds that are under specs.
Just FYI, but I don’t recall this spot being there when I received it last week. I only noticed it two days ago. It’s an XPL-HI LED inside a Convoy C8 from Simon, so I doubt he’d be using subpar LEDs.
You were just being unlucky, either some dust-spec caught fire and burned itself ito the silicon thereby causing some silicon to burn as well, or something was already inside the silicon. It will probably get worse upon use. I’m not aware of Cree selling low grade rejects.
So nothing can be done at this point?
You might be able to get some of it off with isopropyl and a cotton swab, just wet the cotton and rub gently. It looks like the silicon itself does have some burn marks now though so you likely won’t get it all.
Thanks. Tried it. Nothing came off, unfortunately. It must be baked in there for good.
Well that stinks! I would try to remove it with a pin/sewing needle so it doesn’t get worse. Does it impact the beam?
It’s too tiny for me to try going at it with a needle… I think I would just accidentally cause more damage.
I am not seeing any impact on the beam.
It happened with my Haikelite SC01 when arrived. I used needle to remove the dot and cleaned up with isopropyl alcohol.
It looks better now, I still don’t know why did quality control agents let them out like that?
Even a HI has some silicone coating on the chip. Ie, it’s not a nekkid dedomed model.
It’s nowhere near the bond wires, so you can try something sharpsharpsharp and gently poke at it and try to dislodge it. Emphasis on gently. Still might leave behind a pothole of sorts where it cooked itself into the silicone, but the dark spot will be gone.
Fwiw, there’s a similar technique for dust that’s packed onto a DSLR sensor that doesn’t come off with compressed-air or the like. As long as you don’t gouge it, you’ll be okay. Again, emphasis on gently…
It’s like a sugar-stain on a white shirt. Won’t show up at all ’til you iron the shirt, then the stain caramelises and turns brown.
The XPL HI has enough silicone thickness to try to poke that spot or use a razor blade to cut it off
This spot likely will get worse, so removing it is the better option
You can always contact simon on Aliexpress and ask for a refund or spare part, he is usually pretty helpful
I usually clean the LED before use, sometimes some flux from soldering the wires lands on the LED
Looking from the picture, it’s most likely flux splatter from soldering the wires. You can see it’s not the only one, there are some more. Anything opaque will gets hot and burn through the silicone. The harder the LED driven, the most likely this happen.
Try IPA, if it fails then remove with with sharp needle or sharp pointed craft razor. Left, it will get worse and eventually reach the phosphor.
- Clemence
My eyes aren’t good enough to operate on a tiny speck of dirt with a needle, so I enlisted my wife. She got the sucker off, and then I cleaned it again with isopropyl alcohol. Thank you everyone for the advice!
Can’t even tell. Great work!
Wow, did not expect that to work that well! Good job from a great helping hand! 
Ooh! So clean you can eat off it!
Wow, what a difference! Like it was never there. Good job.
