Which lights you have bought that have stopped working and why?
I'll start Aurora SH0032 Cree XPE Q5 - as I was twisting it it started to flicker, contact issues.
Started turn the pill to unscrew it, to take out driver, and the wires broke the driver was pushed into the pill.
Head was glued, $14 wasted.
All other lights working fine.
Update: My Smallsun M10(6Mode) stopped working on AA since I put in a 14500 but my Ultrafire M10(1Mode) works fine with both 14500 and AA.
My TrustFire XP-E F23 died after dropping it while pulling it out of my pocket. I thought it was going to take a lot more abuse than just one 3 foot drop.
Oh well.......
I've bought a great deal of lights and it doesn't seem like any has failed on me. There was one incident though. My Hugsby P32 started smoking when I put in a 14500. It wasn't meant for 14500. Doh! It smells pretty bad every time I open the tailcap. Now it doesn't work with a NiMH anymore but still works with a 14500 
The same happend to my W109. Much to sensitive these LED lights. I droped it from a bit higher though. Just 3 meters to the concrete. Ouch!
It has two ugly dents now and a brand new 5-mode driver with an excellent memory.
The sad thing about mine was, not only did it drop from 3ft (maybe less) but that it dropped onto my linoleum floor in the kitchen. When I first got my F23, it looked and felt like it was built like a tank but looks and build can be deceiving. tsk tsk tsk
TrustFire F20. Working perfectly during 2 months with NiMh. Installed a 14500 and in 2 seconds the driver went POOFFFF
http://www.dealextreme.com/details.dx/sku.28544~r.43033281
Still without receiving the replacement, shipped on 21 SEPTEMBER!
I hope that DOA lights fit in the topic too.
Trustfire XP-E F23 was DOA. Tightened the pill, measured Amps at the tailcap - now there was light!.
Battery in and tailcap on. Dead again!.
Screwed on the tailcap to get it off and suddenly there was light again!. The reason is that the pill do not like the pressure from the battery. It now works fine with the tailcap unscrewed about one mm. To investigate later.
Ultrafire WF-502B XP-G R5 had flicker/no light due to loose pill. Never mind, I was going to lube it and put in a 3 mode driver anyway. Works fine now.
Trustfire Z1 XP-E Q5 came with partly unscrewed head and tailcap. Never mind, was going to lube it anyway. Much worse was the ugly magenta tint and the donut hole. Unscrewing the head a little removed the donut hole but made an ugly, uneven spot.
14500's probably kill more lights than anything. I have killed two lights that way.
One was the Uniquefire S10 6-mode. KD didn't claim that it was okay with 14500's, but DX did. I got mine from KD and stuck a 14500 in there and no more light. I rigged it for direct drive and now it is a 1-mode 14500-only light.
The other was the Aurora SH-035. Now this one was supposed to work with a 14500, but instead it caused a dead short and I'm lucky the battery didn't explode. The beauty of the SH-035 is it takes a 17mm driver so I was able to swap out the fried driver as well as the LED (which I killed trying to get the driver out) and now it is a pretty nice light.
Those are my only two and now they work, so I guess I don't have any lights that have stopped working!
The right way to check for compatibility is with a DMM. Touch the probes quickly as if testing for current and if it flashes up >>1A it's probably a good idea to quit.
Tank E07. Bought 4, one didn't work right out of the box, 2 work about 20% of the time, and only ONE of the four works decently. brutal for all of the great reviews they have had.
My lights:
C78 unfixable pulsing flickering (most likely driver), C3 P4 random flickering (contact issues, due to bad design - avoid), Black Cat random flickering (contact issues, fixed by heavy use of 2 pliers... glued head,grrrr... light now looks like it has been run over by a tank)
Lights I had to fix for others:
2xC3 P4 random flickering (due to bad design - avoid), Skyray S-R5 (dropped from a bike mount - driver replaced), Ultrafire 504B R2 (dome fallen off emitter - replaced with R5), Ultrafire 501B R5 (switch caused flickering.... and driver went poof... now a Xenon light)
The good thing is ... I haven't lost money on anything... If my lights hold up the 1st month, they usually last..
None of my lights stopped working...
I have a C3 with random variable output. Sometimes annoying but still usable - and it seems to me to be close to a feature in this light. I also have a few DOA's that have been replaced by the supplier and never repaired (and probably never will be).
I EDC an akoray 106 that has been dropped down the stairs (and a few times on the floor). Some scratches and dents, but no modification to it's performance. They never face freezing temps or anything over 40C. And I do not throw them at the wall or run my car over them on purpose....
Ultrafire 504B with R2 dropin:
http://www.dealextreme.com/details.dx/sku.24200
The emitter half-baked (still producing some light) even though I stuffed it with aluminum foil the moment I got it.
One BLF Delight refusing to cooperate with a 2AA adapter from another cheapie eBay light.
At first twice that bright, after 10 minutes a faint blue glow.
Mine fell from a fifth floor… Is also not recommended . lol
In this X2000 model, the spring pressure and bad aluminum, eventually wear out the thread of the pill.
In the rest of flashlights, nothing a bit of tin or copper ring can not fix.(I guess I've had good luck)
Perhaps only the Black-Cat does not have the power I see reported by other owners ...
Dit it survive the fall? Could you post pictures of the damage?
c78 was ok with AA
put 14500 and...no signs of life... :(
It was long ago and I did not take pics. Neither I found all the pieces.lol
Fortunately he fell through a courtyard and there was no further damage.
This one worked for half an hour, giving a weak, bluish beam. Now it only flashes randomly. I guess the driver has gone to the driver heaven.
Yes, the thing has a driver and can be run from 1xAA or 2xAA with extender tube.
Nice little thing....
But that is to be expected when you buy a $0.99 flashlight ?.
And the emitter was'nt even a CREE as stated.
Perhaps I can mod it (meaning: using lots of hours), perhaps better to buy a Romisen RC-i3 and save the time....
DO you mean built like a tank the flashlight manufactuer or the Abrams http://www.kaboodle.com/reviews/amphibious-rc-tank-1-10-scale-works-on-land-ice-water-too
Don wrote:
"Your chance of being killed by a F-23 dropped by a seagull from 3 feet while in the kitchen onto the linoleum floor is considerably higher." "I think"
NONE all my lights work ..that is why I'm in such a desperate search for the elusive non workingflashlight ..I'm glad to hear that the Tank 07 is a possible problem i have one of those coming thanks to dons recomendation <<"thanks alot don".. I just can't wait to have something fail so i can cuss and thow stuff .
I've just managed to knock the dome off the LED on my Mrlite J4. Mine didn't have a metal retaining ring for the optic like the one Matt tested. When I took the head off to try the TR-801 reflector in it, the dome came off the LED. Crees without their dome go very, very green. And dim!
It is even greener than the Aurora SH0030 which has been a green monster since I bought it.
I have some unmounted R5's lying around - wonder if they'll work with the J4 optic?
Could be fun finding out.
Guess what I plan to do tomorrow?