A few weeks ago I heard someone here on BLF (sorry, can't remember who and where) mentioning this small light, for sale for 9 dollars at Fasttech. Although it looks like any of those cheap black tube shaped cr123 lights (which it almost is), I thought it was interesting enough to buy one because in stock from it has a xpgR5 and a AK-47A Nanjg lineair driver, stars set on three modes 5%/30%/100% without disco (making it stock already unsuitable for cr123 primaries by the way).
I found it in the mail the day before yesterday, just as I was highly frustrated because of a 219B triple mod going badly wrong. While still mourning about that one, I thought I could perhaps regain some confidence by modding this one. First a picture of the stock light (it performs well, with enough output for such a small light, on a white wall it has a very nice smooth beam pattern, just the switch feels wacky, something about that later):
I thought I'd do some fancy coloured lighting for this picture, because, well, it looks like any of those little lights, except it has no lettering at all, it is all plain black, with an appealing matt finish. It already gets a bit more interesting if you compare it to two others of these type of lights that I have:
This type of light is small, but this new one is the smallest of them all (on the left is the well-known 602C host from FT). Opened up it has a few nice surprises:
The o-ring before the lens isn't an o-ring, but it is flat, it will not easily pop out, the lens is nice and thick, the aluminium pill leaves enough clearance for a not too messy solder blob (even with the insulating gasket around the led removed), the pill is flat on the top (easy to sand really flat for the mod), is not hollow and has a brass driver holder, the switch is a -for this size of light- unusual beefy Omten switch, with the battery spring directly attached and two contacts on the side that press-fit directly to the inside of the body.
The only thing they messed up with this light is that there should be a metal ring between the switch and the boot cap, it is not there and that makes the light not water tight and makes the switching feel really squishy. The first mod was to put a M8 ring (sorry, we use metric over here 
) with the right outside diameter in place and that solved the whole problem: nice firm switch now.
There was a type of thermal paste under the led board that I have not seen before; metallic brass/copper coloured stuff:
The driver showed a few surprises: it is a ak-47, but with one 7135 chip less, and the two that are there are 380mA chips (
). So this light is driven at a conservative but useful 760 mA through the led. On a 550mAh 16340 battery that should be good for about 45 minutes runtime on high.
The mod:
A 219B triple disaster left me with two accidentally dedomed leds, the left one had the dome split open just above the die, only a little corner of the die was removed, and the led still worked, I thought it was a good candidate to mod the little 16340 light with:
I reflowed it on a 16mm Noctigon board, but I thought the board was a bit too thick to fit in this light so I sanded it thinner first, using a unused pill I had lying around as a sanding device (I have wounded my fingers the last time I sanded a led board thinner without a device to keep my fingers away from the sanding paper):
I wanted a 8-chip lineair driver, so the stock ak-47 with room for 3 chips would not do, I went for a Nanjg 101-ak, disco-free (two legs of the tiny13A soldered together), and 4 extra chips stacked. (this little light has no space for chips on the battery side of the driver, so a Nanjg 105C was not suitable)
So that is 4x 350mA + 4x 380mA = 2920mA worth of chips, I will probably not reach that current with a 16340 battery, but it should squeeze plenty of light out of the Nichia :-)
The pill assembly, the pill and led-board were sanded really flat with 800 grit sandingpaper, with a tiny bit of Arctic Silver 5 in between. There will be no plastic spacer between led and reflector, I found that when a led is dedomed a flashlight focusses best with the led sticking just a bit deeper in the reflector:
The switch spring was reinforced with some copper wire, the spring came clamped to the switch lead, on one side I soldered them together (not visible in this picture):
I have no image of the extra ring between the switch and the boot cap, take my word that it is just a common M8 ring.
Done:
White wall beam shot at two meters (because it is expected, but a white wall beamshot does not say much, a camera stands no chance of capturing the intensity range that is in a flashlight beam), you can see the hint of blue in the beam (top right of the hotspot). And a shot at my test-tree at 25 meters (that is not bad, it lights up nice, but in reality it looks a bit weaker than on this picture) :
I measured 2.5A with a freshly charged Efest 550mAh 16340 battery, and at least in the first two minutes a steady 320 lumens OTF, which is a bit lower than I expected. Because of the small led die, the throw is pretty ok for the reflector size: 6klux at 1 meter. The tint of this led is marvellous :-) , a colour temp of about 4000K with very good colour representation. There's a faint bit of blue on one side just outside the hotspot because of the phosfor damage of the led, it gives a personal touch to the beam ;-) . I may be tempted to put a higher output led in it sometime, but it is nice for now.
The mod helped me feeling better after the triple 219B disaster, I hope you liked reading about it :-)
!
