My first mod: Nichia 219 in a Convoy S7

I have a lot of projects I want to do, so I’m trying to learn how. I started with a really simple one — converting a Convoy S7 with XM-L T6 3C @ 2.1A to use a Nichia 219B (~4500K 92CRI). And of course I documented the process, in case it might help anyone else get started with modding.

The 3C tint was good, but Nichia 219 is better. And with a stainless steel host, 2.1A really was more heat than it could handle. So, I decided to reduce it to 1.4A and give it an even better tint.

Here’s the host and its new star: (click for larger version of any pic in this post)

To start with, I have a few tools… This is what I’ve got for soldering: A cheap Weller 40W iron from Home Depot, a cheap “helping hands” soldering station from Harbor Freight, some stereo magnifying glasses from Amazon, tweezers and Arctic Alumina from RMM, and a ZL H51w. Oh, and a flexible desk lamp. I generally put something on the table to protect it while I’m working, too, such as a flat sheet of metal or a ceramic tile.

FWIW, the desk I’ve been using is part of a treadmill desk, so I suppose you could say I like to solder while I’m on the treadmill. o_O

I’m a little new to soldering though, so first I decided to watch some howtos on youtube and try messing around on an old PCI card. I sacrificed a DEC Tulip for the cause.

To start with, I removed some little parts. Most of them either broke in the process or damaged the circuit board (or both):

After that, I got a little better…

And then I managed to remove some of the same parts without destroying anything, though I still scorched the board. I also removed and re-soldered some bigger parts, which seem to have turned out okay.

On the smallest parts, resistors I think, I mostly managed to get one half off without damage but the other half had its connector break off.

And here were some of the parts which took part of the board’s circuit trace with them. Oops:

So, once I felt ready, I went on to the real project. First step: removing the pill. This is really easy with the right tool.

With that done, here is what the pill looked like:

Next step: Remove two 7135 chips to get it down to 1.4 amps. Fortunately, there are two on the back of the pill which are easy to access. I kinda made a mess in the process, but I got them off. The first couple things I tried didn’t work; like, I couldn’t get solder wick in contact with the solder to pull it off. I ended up holding the sides of the 7135 chip with tweezers, lifting up slightly, and holding a wide soldering bit across the three small pins until the chip lifted off. Here was how it looked afterward:

I’m not sure if those 7135 chips are still functional or not, but I put them into my parts bin in case they’re useful later.

Next, I wanted to know if I had totally ruined the driver. So I put it all back together and checked — does it still work?

Yup, it still works.

Next step, take the old star off. Unsoldering the leads was easy enough…

Taking the star out was easy too, since it used thermal paste instead of thermal adhesive. Quite a bit of thermal paste, actually.

Next I tried to put the new star in… but the Noctigon was slightly too big.

The next hour or so was spent making the noctigon smaller. I don’t have a vice or any power tools, so I put leather into some pliers and gripped the star with the padded pliers and held it against a table. To remove material, I used a diamond-coated file I had laying around. It took a while.

I also discovered that the noctigon is thicker than the stock star. This didn’t cause any issues, but I took a pic of the relative thickness anyway:

Right, so after getting the noctigon resized, I put on some Arctic Alumina. I’m used to dealing with CPUs, so I started with a pretty thin layer and put it in to check for contact.

As it turns out, the star made almost no direct contact with the pill. I checked to make sure it wasn’t due to the noctigon still being too big, and the original star actually had just as little contact. I don’t have a lathe or any other tools to flatten the surfaces, so I decided to glob on the thermal paste instead. I know, I know, this isn’t a great idea. Direct contact beats thermal paste any day of the week, and thick thermal paste is especially bad. But I didn’t have a way to fix it, so I filled the gap with something better than air.

You can probably guess how much thermal paste was used based on the mess near the wires:

So, next step: tin the connection pads on the star. Pretty easy, even though I had never done it before.

… and connect the power wires. Again, fairly easy. I didn’t do the cleanest job of it though.

I also got a nifty little XP-G to XM-L reflector adapter, to help center the emitter and protect the star. It ended up being a bit thick though…

The emitter was nicely centered with the size adapter in, but it made the beam ringy. I ended up attaching the old XM-L centering ring to the reflector instead, using it only as an insulator. The beam ended up nicer, but the emitter is slightly off center:

The light still works nicely after the changes I made. Here are some ringy beam shots with the size-adapter centering ring installed:

… and the beam shots with the adapter removed. I like this much better:

After getting everything back together, I took some tailcap measurements. It wasn’t quite what I expected.

  • Low: 0.073A (5.25%, ~46 hours on a 3400mAh cell)
  • Medium: 0.69A (49.6%, ~5 hours)
  • High: 1.39A (100%, 2.5 hours)

I thought the medium mode would be 30% or 40, not 50 Perhaps this will be a good excuse to take the thing apart again later to reflash the firmware. But not today. Today I’m happy just to have a beautiful stainless steel light with the latest high-CRI neutral emitter inside.

Next I intend to upgrade an old UltraFire HD2011 (better emitter, better driver) and increase the throw on a UF-838 (de-domed XP-G2, more heat sinking, better driver). I’m also converting a Blackshadow Terminator to be wide-spectrum (simple emitter swaps), and intend to find a way to flash its firmware. I may mess around with nanjg/attiny13 drivers first though, on something a little easier.

Very nice! :beer:

Good job!

Nice old compass too :slight_smile:

Good job on the mod, nicely documented and pretty decent soldering i must say with just a few tips/tutorials could greatly help.

Looks like a good first mod, much better parts than my first ever flashlight mod that’s for sure.

One thing I will mention, and it’s not a problem as-is, but if you ever plan on taking it back apart for any reason I would be prepared to replace the emitter leads so as to not cause a short, they look like they took a little damage. Again not that bad as is and not something that needs replaced, but I doubt they’ll be up for another emitter swap.

What shape tip did you use? For removing 7135’s I don’t even mess with the wick- just use the flat tip, hold it on the three legs for ~10sec and the entire chip will come right off all at once.

Good Job! All it really takes is some practice and some tools.

This is great!

As a beginning modder, this kind of stuff is helpful. Seeing what worked and didn’t gives me confidence that I’m not totally in over my head.

You sir choose quite the ambitious first mod yourself!

No kidding!!!
I wrote an entire PM to you earlier saying that I am throwing in the towel. I could not figure out how to mount the MCPCBs AT ALL. I soldered the wires, fed ’em through the holes, and tried putting the Noctigons in position, but then the LEDs would not stay under the reflector! I gave up almost!
But then I read someone used thermal epoxy to mount the Noctigons and realized that I was doing it bass-ackwards. Mount the LEDs first, then solder the wires. As it is now, all LEDs are mounted, wired, and the reflector screwed down with no wires shorting out.
Tomorrow I solder up the driver PCB, and hopefully we’ll have a working flashlight.

Once I figured out how to mount the LEDs, I cancelled sending that PM. :smiley:

Awesome job!

Do yourself a favor…get a hot air rework station

For surface mount components and some needle nose tweezers…the soldering is night and day!

Where did you get the stainless Convoy? I see this one from FT…but it doesn’t have that cool clip

Someday, could one of you long-termers do a pictoral on your soldering setup?

What I got is okay for repair jobs, but it is bad for doing intense and or delicate jobs. Heck, alls I got to hold stuff is the crummy alligator clip “helping hands” from Harbor Freight.

Right now, I’d seriously pay good money for someone to teach me how to do high-grade mod jobs. Vinh managed to bang out 60 MM15vs in what I guess was less than a week. I can’t manage one M6 in two weeks. He’s talented, sure, but I feel like my whole setup is holding me back most times.

Great job!

Pretty ambitious for your very first mod! :slight_smile:

That’s a solarforce clip.

well done!

Excellent mod. I was a little shocked to see you used a good pair of dividers for an unintended use but it appears they survived with no damage. Well done.

I used the same method, and it was mentioned in the OP. :slight_smile:
It just took me a few tries to figure out a method which worked. Also, I didn’t know until afterward that the middle pin goes all the way across.

That’s actually why I posted this. It took me forever to finally do my first mod, even after I had decided in detail what I wanted to do. I’m hoping I can help motivate others to take the first step.

Now that I think about it though, I should probably include more details, like pics of the cheapo tools I’m using and maybe some info about where I got everything.

I’ve thought about it… but I decided to start with something cheap as a way of sticking my toe in the water, and I can get something nicer later on if it seems like it’ll be worthwhile. I’m kind of hoping to avoid surface-mount soldering if possible, though I guess the occasional kitchen-stove reflow might be okay if I need to assemble a driver from the oshpark thread.

I got it from FastTech, same as your link. The clip was added later; it’s a Solarforce L2 clip. It’s a little bigger than I’d like, but it does the job. (it fits the Convoy S3 better, but for that you’ll need to cram a paperclip into the tailcap to allow electrical contact)

Oh, the machinist calipers? I got those last year specifically for unscrewing pills and other similar parts. A guy on ebay was selling it fairly cheap and it seemed perfect for the task.

That is superbly documented :slight_smile: Thanks!
What tool did you use to desolder and then solder your stuffs?

I’ve been looking for a nice pair of dividers.
Nice job on the Nichia build. I’m wondering if the Noctigon didn’t sit flat because of the milling at the corner edges. Maybe beveling the underside edges of the Noctigon would have helped.

Oh, and one final mod for the night.

The beam was still less smooth than I had hoped, because the reflector wasn’t designed for a XP-sized emitter. It’s still slightly ringy with a slight dark circle at the edge of the corona. Also, the reflector is deep for its size, so the spill is rather narrow. And since it’s all shiny steel, a lot of light bounces off the bezel to produce a 180-degree wide secondary spill of sorts.

Plus, the tint wasn’t particularly consistent across different parts of the beam. Not exactly ideal for a high-CRI neutral light.

So, I took it apart again and put some DC-Fix on the underside of the lens. That stuff will turn the most crap-tastic beam into a work of art.

It’s now pretty close to perfect, both for indoor use and as a headlight for biking. The main downsides are: stainless steel is heavy, it’s pretty large for an EDC, and the modes go 5% - 50% - 100% with a blink on low to toggle mode groups (so I need to adjust the medium mode down a bit and get rid of the option to add disco modes).

The end result looks a lot like my L3 L10-219, but smoother and much brighter. It’s also a hair cooler in tint (maybe 4600K instead of 4500K), but it still shows colors very well.

well done toykeeper!