need help with my quark mini

I have the quark mini ti and love it I have had it for a little over a year and edc it a lot and it gets used a quiet a bit but I was using it today and noticed that there is a black spot on the edge of the led and it has not always been there and I am wondering what it might me the light still works fine does any one have any experience with this kind of thing ? any help would be appreciated

It's a burn mark, the LED is dieing. The heat produced has nowhere to go therefore it burns the LED.
Do you use it on High a lot?

Have a look at my burned LED the middle is brown, on my Yltrafier MCU C7.

well I don't use it on high a lot but I do some and I also use a rccr123 in it so it is really bright do you use a rc in yours ? thanks for the reply

nathan225 said:

well I don't use it on high a lot but I do some and I also use a rccr123 in it so it is really bright do you use a rc in yours ? thanks for the reply

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There's your issue. It may not seem like you're running on high that much, but it sounds like you're doing it enough that the emitter is starting to fry from the heat. Titanium doesn't conduct heat as well as aluminum, so heat build up is going to be more of an issue with your light than if it had an AL body. To preserve your light as much as possible, stop using RCR's in it and switch to 123 primaries, or just don't use it on high with an RCR.

I had a cheap DX drop in with an XR-E that came with one of these notorious dark spots. I noticed it because it put out significantly less light than an identical drop in, however when I did tailcap current measurements, the LED with the dark spot drew significantly more current.

I am theorizing that when these dark spots appear, the affected LEDs in the LED array turn into shorts and cease the output of light and only make heat.

Were it me I'd retire the light, or look to see if somebody would be up for fixing it by replacing the LED. I'm sure somebody would even be willing to give you a few bucks for it in the marketplace as a project light. However using it as is I suspect you'll see significantly less runtimes with higher heat output and lower light output.