Current Mod Finished! Thrunite TN31 Hi.

9/18 Update on post #41.

Edit 9/12 Yesterday the 32mm mcpcb came in the mail! Couldn’t do anything all day until now. Putting hardwoods down… Not because I wanted to, no, but because we have a little puppy that hasn’t quite figured out the difference between outside and any square inch of carpet… Got the XP-L Hi flowed onto the mcpcb. Now it’s got me all excited, but stinks that I have to wait for another driver to show up in the mail. I ordered one from Acebeam for the K40L and another TN31 driver from Thrunite. Hopefully they will show up soon, but I think they are shipping the truly snail mail slow boat world tour from China. Anywho, here’s the pic of the flowed led. Enjoy!

Edit 8/29 Alright then, looks like I’m modding my TN31 now. Definitely have the led and mcpcb on order. I’ll try to update the OP with my progress as I go along. I’m still new to the forum progress posting thing, so bear with me!

Unable to leave well enough alone, I want to mod my thrunite tn31. I’m really thinking about putting an xp-l hi in it on a new mcpcb. Probably the resistor mod on the driver to bump up the amps. I like the idea of a factory dedomed led, because to be honest, I’ve messed up enough dedome projects to make me real nervous. What do y’all think? Is it worth it to mod that light, or should I look at building one from a more budget friendly host/flashlight?

Oh yeah, it's worth it. The light is pretty tame stock. Put a solder blob or wire over the sense resistor bank and dedome turns the light into a serious light saber. There are a ton of contact points in that light. So cleaning them up to make sure they get good clean contact can make a difference too. There's a thread around here about modding that light.

I’ll have to see if I can find that thread! I love the light, I just want to see how far I can take it! Probably gonna have to make saber noises each time I turn it on!


Very careful about this a long time ago change the driver and this is no longer possible…if old generation is possible :wink:

^Any tips on how to tell if you have the old or new driver?

Found the mod thread I was thinking about. Solder blob sense resistor bank starts around post 150.


You participated thread :bigsmile:

Thanks for those links, it’ll save me a bunch of time searching! Gonna work on getting the thing apart tonight. I’m definitely thinking xp-l, just gotta find a 32mm mcpcb to put it on. Off to the interwebs!

gaston01 wrote:


You participated thread

HA! Must have been an impostor. I would never forget something like that!

You're not buying that?

I tried. Yeah, it sounded familiar when you mentioned it, but I was too lazy to search. Before you mentioned it, I did forget about that case. Thanks for alerting gaston to it. If he has the new one, you may have saved his driver.

Best of luck gastontru3s1lv3r. It will feel like a very different light when you're finished. I'm curious how the beam pattern will turn out with that emitter. Please keep us posted. I may have to copy you.

I’ll definitely keep my progress posted. Already got the mcpcb on order, about to pull the trigger on an xpl hi and some resistors. Probably gonna solder one on top instead of a blob of solder. Definitely gonna polish and beef up the battery carrier. Still trying to get the head apart, though. I’m having trouble getting that dang glue unstuck!

That damn thread lock. As you probably know, it takes heat to melt it. I did mine by putting the head in a bag, placing the plastic bag in a boiling water for 5 minutes. When I pulled it out, my strap wretches could not grip (due to low quality). I had leather gloves on and cranked on that baby with all my strength. I had to put it down several times to cool my gloves. It took a while and just when I was about to give up, it started moving. Even after it started moving, it was a hard slog unscrewing for many turns.

My take away was that boiling water brought it a temp that softened the thread lock, but didn't completely melt it. Maybe more time in the boiling water or a higher temp are needed. If I were to do it again, I would boil longer. If that didn't work, then I would use a heat gun cautiously to bring the heat up to 250F-300F.

Obviously, take care not to burn yourself. Sure you know all the above, but said it just in case.

Yea, definitely took some doing! I started off boiling it in a bag for a few minutes, then ended up using a small torch to heat just the area at the joint. It finally gave it up though after several minutes of cranking on it. Now that it’s open, time to start soldering and polishing. Just ordered the led and some resistors from digikey. Stinks that mtnelectroncs is sold out of the 32mm xp mcpcb’s. I really could use a US supplier right now!!

Congrats. That was the hardest part for me.

Too bad that monster base can't be used for the XP-L. That stock base is serious business. We need trade thread for when some one needs a part like you do now. There has to be some CONUS members that has one of those bases sitting idle. Guess you could do a WTB thread.

Looks like identifying the new verses old driver is pretty easy. The below pics are from the threads linked to above.


(New on left, Old on right). The old is actually from a K40, but the drivers are reported to be the same:


Notice the sense resistors are now on the top of the driver on the far right next to the large yellow tantalum capacitor.


If you don’t mind an older model (meaning not the very latest version), Amazon has the TN31 for $69.95 Prime shippable in both cool white and neutral white.

Yea, here’s the back of driver from mine. It looks similar to the older one.

I’m assuming those two resistors to the right of the spring are the sense resistors.

So far I’ve done a little work on the switch pcb. Beefing up the springs with some copper braid.

I’m gonna get some progressively fine grit sandpaper and truly polish the ends of the battery carrier.

I’ll keep posting as I go!

Edit! I Guess I should also note that I ordered the 32mm mcpcb from int-outdoor. Hopefully it’ll show up in a few weeks.

I think this light for $69.99 is a bargain for such a quality light. I have used a couple of the excellent xp32 noctigon mcpcbs with the extra thick traces and thought i would mention the - and + pads are on one [ when wired for single led] side meaning that both wires have to be directed through one shelf hole leaving one wire short which in my case i resoldered a longer neg wire to the driver.
Looking forward to your updates tru3s1lv3r.

Hmmm, you seem to have a TN30 driver there. That driver can do a lot more than the TN31 driver. For instance, it can drive a higher Vf emitters. The TN31 driver can only out put like 4.55V. The TN30 can drive 3 emitters in series. You could probably drop an XHP50 right on your stock MCPCB and have a heck of a light. Wouldn't be a pencil beam thrower, but it would be very nice light useful for many situations.

I’m seriously thinking of buying another Tn31. Only $70 on amazon. May be another project later on to throw one of those xhp50s in it. I really like the light, it’s really well built!

^ That really is a good price.

A normal TN31 couldn't drive an XHP50. Well, unless it has the same driver as you have. Your driver may be configured in a way that it can't drive a XHP50. You can try it and see though. I won't hurt your driver. It just won't be able to light up the emitter if it can't. Do you have a 6V emitter like the MT-G2 or something? The way I tested my driver was I connected long leads to the driver and reassembled the lower part of the light. I then connected the leads to an MT-G2 in another flashlight head.

I thought all the drivers have “TN30 Series” written on them, at least I know my TN31 does. I think its the same PCB but they use different components on them. I think others already tested the ability to drive a 6v emitter and it wouldn’t work.

For what it’s worth, on the old driver like that one I wouldn’t bother with stacking resistors. Just remove them and bridge with solder. Virtually everyone who has modded those lights has done that without an issue. I did it a long time ago with my TN31 and have done probably 5 or 6 Supbeam/Acebeam K40s and besides the latest one which had the new configuration driver I am yet to blow an emitter doing this mod. But if you are concerned about something happening stacking the resistors will be safer I suppose.

I will be interested to know how you go with the XP-L emitter. I am currently modding a TN32 for myself and was considering trying a different emitter perhaps even a de-domed XP-G2 S4 but I am yet to decide.

Even the TN32 driver has TN30 on it…

The TN31 isn’t in production anymore and isn’t available from the usual sources so that is a really good price for a great light!