Ooh, I'm interested. What was the guidance you received?
Preface
I had wanted to learn basic modding for quite awhile, in particular how to swap emitters, and the excitement generated by the Nichia 219 was timely as I was finally ready to give it a go. Before I could have even considered doing this, I needed guidance from experts because I had zero knowledge of micro-electronics or soldering.
Removing and reflowing an emitter is easy enough as I had practiced, but getting to the board on the D25A, in fact probably in most lights, was another thing altogether. Although I had read a multitude of reference materials and had watched many YouTube tutorials, it's still my nature and was a requirement in my career to know everything about a subject. So much of the additional knowledge and guidance I received, in the form of answering my specific questions came from Jamie, Vinh Guyen, and Gene Malkoff. For this particular mod, Jamie was especially helpful!
The mod
> To remove the stainless steel bezel ring, I used a 1/2" rubber insulated clamp like
this, and small, curved jaw vice-grips to twist it off. It did not show evidence of any adhesive, so it seems to have been simply tightened down firmly at the factory. When lifting the ring off, the lens will fall out, so be careful not to lose it.
> The reflector is secured into the bezel with an o-ring, but only required a gentle pry with my finger tips to get it out.
> Since the board was secured with a white, thermal paste (Fujik?), I figured I could remove it. So I placed the bezel into the jaws of a hobby vise and went at it.
> I desoldered the leads and carefully pulled the board out, trying not to get paste all over the place. Unfortunately, as I removed the board, I did get some paste onto the exposed end of one of the leads. Re-tinning the ends before I pull out the board would make removing the greasy paste a lot easier, otherwise it gets into the individual strands as it did in my case.
> I removed the thermal paste off of everything, the back of the board, the pill, the walls of the bezel, and especially the wire leads using isopropyl alcohol (91%) on a Q-Tip. I then re-cleaned with
Arctic Clean.
> Using my Bernz-O-matic micro torch with blower attachment as seen
here (~$26 from Lowes), I removed the XP-G S2. Since I didn't have any solder paste (ordering today) to prep a new board, I reused the stock board after cleaning all the pads with Arctic Clean.
> Then I reflowed the Nichia 219 to the board with the correct orientation. Using the spec sheet for the 219 (thanks to Craig Shih of Illumination Supply), I was able to determine that the cathode on the 219 was the tiny arrowhead on one corner.
> Before replacing the board only to find out that there is an issue, I first tested that the emitter worked with a couple of wired magnets (thanks Jamie!) to a CR123 cell.
> I laid down only a small bead of
Arctic Silver 5 thermal compound onto the pill (heatsink) because as I had read, too much impedes the heatsinking process. I also read not to spread it out onto the pill prior to placement of the board, because doing so could lead to air bubbles.
> I carefully straightened the wire leads up along the walls of the bezel so that when I replaced the board, the leads would be aligned with the cutouts. I carefully lowered the board into place and as I attempted to center it, I placed moderate pressure onto the board (not the emitter dome!), so that the AS5 would spread out completely underneath.
> Using tweezers and forceps, I manipulated the leads to make them both easier to tin, and to have them lay properly onto the pads before resoldering. Again, next time I will tin the leads after I desolder them, but before I remove the board.
> I then immediately replaced the reflector so that I could be certain that the emitter was centered.
> I cleaned the lens, but before I replaced it, since I wanted a floody beam for this light, I laid it on a tiny piece of diffusion film and cut around the perimeter with a hobby knife. I then placed the lens, diffusion film-side down, on top of the reflector and screwed the bezel ring back on. The end!
I know I get wordy, but I hope that helps!
-John