SF L4 just failed

My SF L4 has just failed. The LED has begun flickering and looking at it, there are several "lines" in the LED that flicker, then usually only one remains lit. It glows brightly at first (sometimes), then drops down to a very dim level. At times, when I first turn it on, the entire diode lights up normally, then drops down like that after a second or two. I've also noticed that the KL4 seems to generate the same amount of heat as it would if it was working properly, even though the lumen output is probably less than one lumen. The problem doesn't appear to be in the switching mechanism or batteries either. Has anyone else had this type of problem with the KL4?

Thanks

Call surefire first thing in the morning, i dont know too much about that light, And the LED is probable fine, perhaps there was a failure in the board?

hmm sounds like the actual led if only part of the whole thing is lighting up. The luxV is in a series/parallel agrangement. I remember another thread like this one. I wonder if the led is no longer in good contact with the heatsink on some lights?

if only 1 part of the LED is lit and the other are not, than the LED itself is fried. call surefire and they will replace the head for you.
explain to them that the LED is not all lit.

Yes, like roguesw said, if only a part of the die is lit, the LED is fried and has to be replaced. Surefire will do this for free.
Just curious: Did you try to run it on 2x R123 Li-Ion cells?

I had a similar problem, I overheated the LED which in turn broke the seal in the head, which in turn broke contact on some ground inside.
Surefire replaced it in the 6 week window they gave me when I called for an RMA, I got a perfectly white, donut free KL4, they even threw in a set of batteries.
Mine went intermittant in a similar fashon to yours, partial to no output.

Thanks guys. The biggest problem with returning it to SF is that I won't have a flashlight for the next 6 to 8 weeks. The LED has at some points lit up completly for a brief second, then dies out almost completly. Jan, I never ran it on 2 R123 cells, however I have used a Pila 600S. Do you think this may have caused this problem? I don't see how it could as it technically puts out less than 4 volts as opposed to 6 from standard batteries. Also, I noticed that the light ran cooler with the Pila batteries as opposed to the primary cells.

Does Surefire offer any sort of expedited repair?

6-8 Weeks is quite a long time.

I feel for you, hang in there!

Yeah that doesn't sound good, definitely a LED field failure. I guess bad things happen even to good folks.

Hope for the best, but I would recommend picking up something like a Fenix L1P or L2P from lighthound.com in the meantime just to tide you over. At $35 they aren't too costly and they run on alkalines/NiMH. Not the same class as an L4, but adequate. The L2P is reasonably bright.

Any word Aaron?

Always a good idea to have spare back up light. Would be great for when somethign like this happens.

Aaron said:

Thanks guys. The biggest problem with returning it to SF is that I won't have a flashlight for the next 6 to 8 weeks. The LED has at some points lit up completly for a brief second, then dies out almost completly. Jan, I never ran it on 2 R123 cells, however I have used a Pila 600S. Do you think this may have caused this problem? I don't see how it could as it technically puts out less than 4 volts as opposed to 6 from standard batteries. Also, I noticed that the light ran cooler with the Pila batteries as opposed to the primary cells.

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Aaron,
No don't worry, the Pila 600S should run the L4 just fine.

Jan