Here is a tutorial on how I modded the thruNite TN-31, I did the mods over several days, and the results are well worth it! :bigsmile:
Sorry but the SD card where I had the pics became corrupted! :_(
To open up the light and to access the emitter you need to put the TN-31 head in a plastic ziplock bag for 2 minutes in boiling water then use strap wrenches to open it up.
Be careful not to loose the tiny steel ball and gold spring that are under the metal brightness selector ring, remove them and put them inside a ziplock bag for safe keeping along with all the screws, LED centering plastic ring and O rings.
1 Using a very hot soldering iron unsolder the wires to the LED, the manufacturer seems to have used a high melting point solder or the copper absorbs the heat pretty fast, so use a thick soldering tip with at least 40w iron or you will not be able to unsolder the wires.
2 Remove the plate that covers the circuit board by removing the 3 screws that hold it in place, put screws in plastic bag and notice how the black plastic insulator goes installed on the plate, remove and polish the aluminum plate to a mirror shine using Flitz and a dremel with a polishing wheel.
3 Replace awg 26 stock silicon wires with awg 20 PTFE or Silicon wires, be careful not to bend much the negative wire once soldered or you will tear off the pad! I sugest you pre solder the wires before installing.
4 Install an extra R082 smd resistor, you can buy them from Digikey, it will increase the current to something between 4.6 and 5A
5 Remove PCB By Removing the 2 screws that secure it to the heat sink, put screws in plastic bag.
6 Clean the PCB from thermal grease with de natured alcohol and Q-Tips
7 Remove what appears to be a kapton tape layer from under the copper PCB and lap to a mirror finish using 2500 grit sandpaper and flitz polish. I got no clue what were they thinking for leaving tape in there!
8 Replaced the stock XM-L U2 with a XM-L2 U2 1C emitter from illumination supply, I direct bonded it to the copper of the stock PCB by filing off the central pad’s dielectric layer with a dremel, do not put too much presure and over do it, stop once you see the copper.
I used a heavy tortilla iron skillet in low heat to replace and reflow the emitters, be careful not to over cook the emitter.
9 Polish the heat sink to a mirror shine using Flitz to maximize heat transfer between the copper PCB and heatsink.
10 Polish using Flitz the 2 contact pads of the heatsink where it makes electrical connection with the circuit board, there is a lot of gunk there! once you finish cleaning and polishing clean it with alcohol, then deoxit then use progold as a final coating.
11 Use the soldering iron to put more solder around the base of the spring of the circuit board
EDIT 8/12/13 I soldered a copper braid inside the head spring (+) contact (Kind of like the old Mag Mods) to reduce the resistance of the spring, also added copper braid to both springs in the tail cap switch, apparently there is a slight increase in brightness by doing this mod, keep them small and be careful to not short out the springs.
12 Clean the gold ring pad on both sides of the circuit board using alcohol, then deoxit and finish with a coating of progold.
13 Re install the circuit board but before you put the polished plate back, clean the underside of the plate where it touches the circuit board with alcohol, deoxit and put a layer of progold. Do not over tighten the screws.
14 I used Arctic Silver 5 as my thermal compound, I completely covered the back of the polished copper PCB using a spatula used to spread thermmal compounds on computer processors, make the layer as thin as possible.
15 Before you install the PCB notice what side is the positive and negative so your wires match.
16 Re install the PCB retaining screws and do final adjustments to center the led in the heatsink. Tighten up the screws real good but be careful not to strip them.
17 Re solder the thicker wires to the LED and re install the centering ring making sure it sits flat at the base of the PCB. Use lots of heat and flux, be careful not to touch the dome with the iron! If You can use something to cover the emitter while you solder, it will be much better.
18 I used super lube thick grease on the selector ring, makes the switching of modes smooth as butter! Fill the hole on the underside of the selector ring with grease then insert the gold spring and steel ball, then grease all the detents and flat surfaces of selector ring and align the triangle marking with the stand by marking on the heatsink and re install, test for proper function and then re install o-ring.
19 You could put some thermal grease on the tread of the to help transfer heat to the massive head.
20 If you did everything you should have a VERY bright light.
Next stop, modding the battery carrier and switch…
PS. let me know if I missed anything!