So first off hi to everyone, been a lurker for about a month but a little problem pushed me into getting my account.
Probably everyone here has one(or plenty) of sk68s and i'm no exception, even though i just started and only got 2 flashlights including the sk68 (and 7 flashlight on the way plus a nitecore I4 charger so i think i'm well oriented ), and so my problem with this is that, well very simply it just stopped working. After i insert the cell, any cell (14500 or AA) the readings i get on my cheap DMM are 0A and 0.2ish V, BUT after i remove the cell if i connect my DMM to the torch itself (#nocell ) it reads 4.0 or 1.2(the cell ratings!) and goes down fast(no readings on the amps)!
I do not know if this is normal or not but my other flashlight do not do this(the so called Ultrafire E17 on AliExpress).
So if someone knows a solution please help me (the seller already send out another one but is always to have another). If not i was thinking of direct driving it but im not sure if it is a good idea so some guidance would also be nice
P.s.: If you require any type of photos please ask!
Spin the head clockwise…it might have unscrewed the pill a little bit
Also look down into the battery compartment at the driver, see if the + pad is all gooped up, if so get a q tip and some rubbing alcohol and clean the contact
Thats not the problem, i have dissassembled the the flashlights variou times now looking for something wrong i even tried take readings directly into the pill with a 14500 but i tried cleaning the driver with alcohol and the abnormal readings did disappear the flashlight still doesnt work but i notice something,there is a little copper coil in the driver coiled around a magnet-like material(it just seems normal fridge magnet) and it is broken i dont know if that is a problem but that is the only abnormality i can detect
Not a magnet. It’s the ferrite core of the coil (spool).
Bits break off easily, which changes the induction of the coil, lowering the µH (micro-Henry) of it.
When a small piece breaks off, is usually not a problem.
For the rest you’re not too clear about where exactly you measured what.
Yeah, that is the coil that is part of the boost circuit for the 1.5v (AA) running mode, with a 3.7vdc Li Ion (14500) it acts as a linear regulator.
Can you take a 14500 and two wires, quickly touch the polarity to the driver (ring on outside is ground, center spot is +) and/or to the solder joints on the star (see if the emitter is still working)
If you smoked the driver, you might have to either buy one (there are no 15mm boost circuits…closest one is a 13mm from FT, or one of the custom ones from OSHPark
Take the tailcap off and use a length of wire to jump the connection between the flashlight housing and the battery. It could just be a failed switch. Be sure to touch the non anodized part of the housing for a good connection.
more or less making a copper o-ring then soldering to the outer ground ring
wight made a large PCB dropin type adapter plate but when you get that small the PCB becomes quite fragile
driver shimming
Truthfully I would like to get one of those 13mm PCB’s, get a picture of the components, then strip one with a hot air rework station, sand off the green solder overlay, get the trace design, get a schematic from the trace design, then make a OSHPark board in 15mm size, then all someone would have to do is get the 13mm driver and move everything from the 13 to 15 (or build one scratch with mouser or digikey parts)…ALOT of work but a viable option
Kind of like what people did with a Nanjg 105C (not sure who posted images before maybe comfychair or rufubuck…there are so many that have led in this area)
I'm sorry for the delay, i did post two messages but for some reason they're not posted, might be my cellphone's fault.
I did did all the tests you advised but to no avail.
So i figured that the problem was the driver as i connected a 5v 400ma power source to the LED and it worked, so i thought, as said before, of direct driving the torch.
Very simply i removed everything from the driver and filed a little to really remove everything then i pierce a very little hole on the middle of the driver, where i soldered the positive wire and soldered the negative one on the negative part of the driver. As predicted only works with 14500 and pulls 1.3A.
Yeah…1.5vdc won’t light up the Cree emitter, its Vf is approx 2.7-3.3vdc
Running a Li Ion direct drive is a bit hard on the LED so be careful and make sure you don’t over draw your battery, there is no protection at all now…if you pull your 14500 below it’s safe discharge level you effectively kill the battery even though it has 2~vdc in it
Thanks for the information, but that's not a problem since i'm overzealous about my batteries and bring my DMM almost fused with me
And i never use my sk68 for long anyway mostly a few seconds! But it does get hot sometimes even hotter than my XM-L on high! But then again this flashlight is much smaller.
), and so my problem with this is that, well very simply it just stopped working. After i insert the cell, any cell (14500 or AA) the readings i get on my cheap DMM are 0A and 0.2ish V, BUT after i remove the cell if i connect my DMM to the torch itself (#nocell 
) it reads 4.0 or 1.2(the cell ratings!) and goes down fast(no readings on the amps)!
