Thanks. Your text and photos give me a good picture of how to disassemble a SRK or clone. My two have driver boards marked JB and JB-A on the battery contact sides. JB-A on the black SRK and JB on the SecurityIng. Red finish, I presume solder mask, on the non copper visible board parts on both. Both are 5 mode lights as received with 3 levels plus strobe and SOS.
Nice detailed work… 
Does it get hot faster than with the old SRK driver on HIGH mode? :bigsmile:
Good writeup. Others on BLF have wanted the modes in reverse order as well. IIRC the fix a simple change, but you must be careful not to mess up the Turbo step-down (assuming you are using that). I don’t have a link to a post right now.
Maybe the change was as simple as:
if (press_duration > 0 && press_duration < LONG_PRESS_DUR)
vs
if (press_duration > 0 && press_duration > LONG_PRESS_DUR)
Excellent pictures! Very nice build! :bigsmile:
Oh and nice leatherman squirt. I’ve been keeping an eye out for a squirt PS4 with torx pivots.
What an amazing story. I love your persistence and applaud your effort. My daughter is not much into lights but liked your nail(s). Whats next on the modding list? You have set your bar at a high level. Again well done. 
Yes, it gets warm pretty fast on the highest level. To be honest though, I try to avoid leaving any light on the maximum level for very long. I haven’t actually left this on turbo for more than 20 or 30 seconds yet, but even that is enough to turn it into a hand-warmer.
It definitely heats up faster than my Blackshadow Terminator… but then, my ceiling bounce test also tells me that this is significantly brighter than the BST.
As for mode order or UI button mappings, I don’t even have any flashing hardware yet. Firmware might be my next adventure, and I’ll probably be doing a lot more than just swapping the button mappings. However, that simple change might be a good “hello world” type test, to make sure I have the toolchain working.
The Squirt ES4 is new to me as of a few days ago. The TSA took my Juice S2, so I decided to try replacing it with something smaller and better-suited for modding.
Fantastic job. I have one question.
What is DC-Fix exactly and where did you get it?
Edit: yea I know that’s actually 2 questions.
Heh, nail(s)? 
This was the first time I ever tried nail wraps. A friend just got into them and gave me a sample. I didn’t really like how it turned out though, and finally took them all off this morning except for my thumbs. They’re kind of holding together some tears in both thumbnails, so I’ll wait until that part is grown out.
The problem with nail wraps is… well, have you ever tried to wrap a piece of paper around a globe… without allowing any creases in the paper? Same problem. I like regular nail polish much better.
Anyway, that was kind of a tangent.
The next mods on the list are: Start writing attiny13a firmware, and make an aspheric thrower with de-domed XP-G2. But I don’t have the hardware yet for flashing firmware, and I’ve been dragging my feet on the aspheric mod because it has a hollow pill and I haven’t bothered to find the raw copper I need to build a heat sink. It might be better to just get a UF-T20 to mod instead (much better host and better thrower), and leave this one (UF-838) as only a flooder.
Oh, and I still need to post about making a light box, and still need to make an integrating sphere. And figure out how to properly calibrate them.
And then there’s the 1x18650 variable-speed strobe light. And some others.
I hope that the excessive detail and pictures will help other inexperienced people get into modding lights. At the very least, I think it shows that a lot of mods are actually pretty easy. It doesn’t take much to turn a budget light into something awesome. (I think it took less than an hour to upgrade my HD2011 to a Nichia 219B w/ Qlite NLITE driver)
Awesome mod! Love that 32*7135 build…glad they are working out for people…Mattaus did an incredible job with that build! Really pushes the amps if you have good batteries
Definitely want to see beam shots and your take on the clarity of the colors you get with a wide spectrum flashlight…I know with a neutral tint emitter (4C) the colors look that much distinct and clear rather than running a warm (yellowish color) and cool (bluish color) now with all three all the colors should really stand out and be that much more vibrant!
Excellent job and build…I am going to do the same with my 3*XM-L SRK but instead of XM-L’s going to convert to a quasi thrower with XP-G2’s in it, run at a little hotter than 300% output 1750mA, XM-L’s run at 3A at 300% output, XP-G2’s at 1500, but they get hot reaaaaly fast! (and my SRK doesn’t have a heatsink…so after ordering a 50mm copper round [20ga] will build a heatsink shelf and then bond the sinkpads to that.)
Love the build
It’s a diffuser film, intended to go on windows to let light through without allowing anyone to actually see what’s happening on the other side.
What I got was “DC Fix 3460211 Sand”, and it was $20 for a lifetime supply. Well, a roll 45 cm by 200 cm anyway, which for torches is more than I’ll ever need. You can also get envelope-sized sheets from some community members for a few dollars, but I knew I’d probably use more than that so I just got a whole roll.
I got mine from Amazon, but that was just because it was more convenient than ordering from Germany (where it’s made, IIRC).
hehe Mickymouse is happy!
I like the thread. Never modded before and it gives me a good idea on what's involved.
Beam shots… I can do that. Probably some with and some without the diffuser film. And even more interesting are the shadows it casts, since they have multi-color edges. But I can’t really get pics to demonstrate how vivid the colors are. All I can say is that my BST-wide produces the best color of any light I’ve ever used, including nice Nichia 219 neutral high-CRI lights.
As for the XP-G2 thrower mod, why stop at 1750mA? I’m not sure how much heat a SRK host can really take (especially if you must build the heat sink yourself), but the XP-G2 can run at 3A or 4A with sufficient heat sinking. You could use this 32x7135 driver for it. And if you want it to be extra throwy, de-dome the emitters first. I hear you can get 125 kcd of lux with de-domed XP-G2s in a SRK. I think 18sixfifty has made some like this… more lumens than a stock SRK and about 5X as much throw. Even if the host can’t really take that much heat, you could still use it as a “turbo” mode.
Oh, wow. I didn’t even notice that. I think I must point this out in the OP.
Also, I’m glad it was educational for you. That’s why I posted a write-up.
The Oshpark boards are thinner than the original drivers which is why your tube-to-head alignment changed (also in some cases the ground ring on the driver won't even touch the face of the battery tube, and the light only works if the ground is carried thru missing anodizing on the threads). I add solder blobs and then mill them down to the same thickness as original, though you can use anything as long as it's the right thickness. Nonconductive is actually better, since a lot of lights have flaky anodizing in the threads and won't lock out properly if the driver has a ground path to the head (it only needs to touch the battery tube).
Also, if you have the stuff to do it, reflash it with a fast-PWM version of the firmware. It's much quieter and still works fine on both the 7135 and FET drivers.
Awesome job on this mod ! great idea of the tint blending to achieve a good balance. would be great to see some beam shots comparing it to other lights of single tints.
Yeap that’s the solution. You won’t be able to ‘re-thread’ it. That’s not something you can change.
Oh, I re-threaded the lanyard. It was easy and took only about a minute. Now it attaches almost directly underneath the button again.
Fortunately, this was an original pre-clone SRK and has good anodizing and good lock-out.
Whatever firmware RMM put on it (“SRK Special” STAR firmware), it doesn’t make any sound that I can hear. I don’t think I’ll need to change it for noise reasons, but I would still like to play with firmware in general.
Edit: Also, I’m not sure what speed the PWM is. I haven’t checked that yet. However, it looks faster than a typical 4.5 kHz nanjg. I’m just not sure if it’s 9 kHz or 18 kHz. I’ll try to compare it against my XinTD C8 V4 (18 kHz) to see if I can figure it out, but my method isn’t very precise… just waving a thin white sheet through the beam as fast as I can, and trying to estimate the distance between “frames”. At 18 kHz, I can barely move it fast enough to see frames. Regardless, it runs silently and the PWM is fast enough that I haven’t noticed it when not looking for it. (at 4.5 kHz or below, I see PWM even while I’m not trying to, and it’s distracting)
great thread!
A-grade pictures
nice text!
thank you for sharing.
A great mod and a very instructive thread! Thanks for sharing!