KR1 won't turn on.

EDIT - My KR1 is perfect. The Orbtronic 18350 works fine. Tip? Don’t use the lanyard ring with the 18350 tube.

—I just got a KR1. Beautiful, feels great, but it won’t turn on.

It just flashes rapidly if you hold the power button, brighter and brighter, then shuts off.

A single press results in one tiny, dim flash.

Positive toward head, negative toward tail, fully charged known-good Orbtronic 18350 in 18350 tube.

What am I missing here?

Orbtronic 18350 is protected battery?
It’s simply too long for KR1, the tailcap does not make fully contact with the tube.
Please use unprotected battery, and make sure the tailcap is fully/tightly screwed in.

I will check, I thought I made sure to order unprotected.

The power button pushes easily, is there an easy first “click” then a harder second click?

I’m afraid to damage the light so I haven’t pushed real hard.

If it’s unprotected, then please make sure the tailcap is scewed in tightly until it can not move more, please don’t worry, it will not be damaged.

This is actually a FAQ, “The light only blinks when I hold the button, is it boken?”

No, it means the tailcap does not make fully contact with the tube, all you need to do is to screw the tailcap tightly enough.

KR4/KR1 tailcap needs be to be tightly against the pocket clip so that it does not move freely.

I’ve screwed it together pretty tight. No change.

Please check the PM.

Ok, so I tried an 18650 and the light works great.

The Orbtronic batteries work in my D4V2 mule, but not in this light for some reason.

I’m glad it was pretty simple.

The light looks and feels great.

The attention to detail is evident, as it is in every Emisar/Noctigon light.

I posted this thread here because I thought I’d get a faster response than if I’d contacted the manufacturer. My experience is that most manufacturers get back to you in a day or so.

Literally less than 5 minutes later Hank himself steps into the thread to help.

Now that’s customer service.

Thanks Hank, I can’t wait to see what else you come up with.

this was awesome to see

I have a KR4 and had similar results with the 18350 tube. It definitely has to do with the length of the cell.

Firstly, make sure the short tube is oriented correctly. (More threads side screwed into the head)

If the cell is not too long and the tube is oriented right, you should see no hint of the red o-ring on either side when tightened fully.

The short tube works fine for me with an unprotected 18350.

You are semi-engaging factory reset mode when holding the button down, because there is intermittent signal contact (which simulates the factory reset operation of unscrewing, holding the button, and tightening.) Your light does not have good electrical contact with the 18350 tube. The KR series of lights is very sensitive to fitment due to the signal tube design. Check the FW3A FAQ as well, basically the same problems.

If the problem does not resolve, carefully clean the ends of the signal tube and body tube with isopropyl alcohol and allow to fully dry. Screw light together making sure the head and tail are both fully tightened.

Continue to try loosening and then tightening the head and tailcap. If you continue to see no improvement, check the signal tube for any burrs, if so you may need to gently lap the tube end on high grit sandpaper to smooth it out. This is a last resort as you must be careful not to remove too much material. My KR4 tube made poor contact because there were some burrs on the end that prevented full engagement, which very gentle lapping resolved.

Good information, thanks, friends.


Hank (or anyone) please help. As of the last 2 weeks my KR1 has been going through bouts of not turning on as well. I have not changed anything with my setup (battery - sony vtc6). What i find is that there now seems to be a “sweet spot” of how hard / not hard I tighten the tail cap. Or it is just the act of me loosening and tightening the tail cap that jolts into working again? It’s not horrible, i just hope it doesn’t get worse. Its surprising as it seems like the KR1 is one of my best made lights. Please advise why this random not working, adjusting the tail cap threading and then it works, might be happening. Thank you!

Try cleaning the contact areas.

I will try this when I get home, thank you!

I have the same issue of my several KR1 and KR4 not turning on sometimes. I have to tighten the threads real hard to get good contact, so it is just an issue with poor contact. The problem is not as frequent as with the FW3A, where I suspect is a driver issue causing it not to turn on. Hopefully the Loneocean driver that will come installed in upcoming FW lights from Nealsgadget will fix these issues.

Good to know about the KR4/KR1. I have only been having the problem recently with my KR1. My KR4 I have owned longer, and is BY FAR my most used light (pretty much every day pocket carry) and i have had no problems… Also i own 2 fw3a’s and have not had this problem with them either, sounds like i am lucky with this. I feel like i read somewhere on BLF that you can slightly sand down the inner +/- contact tube’s length to create better fitment/simultaneous contact of battery and tube to driver/neg. contact? I could be making that up though…

Also, is the Loneoceans driver in the fw3a really happening? I thought i read that LO wouldn’t be able to deliver on that? I hope it does!

Correct. This is the nature of these double-tube designs. They are finicky, sometimes you have to unscrew them and rescrew in a particular order. Plus the tail needs to be very, very tight.

Hank’s flashlights are aimed at experienced hobbyists, thus the buyer should already know this from prior experience.

The tailcap needs to be tight because of the clip/lanyard ring and its o-ring. If you remove it, even screwing it on very softly is enough. And with the spring for the inner tube there are no such issues as with the FW3A. The downside is that the inner tube has not much force and if the contact areas are not clean it will have issues.

I am new to this and “becoming” a hobbyist(?) so it makes sense, i do not know much. Also, I think because I had no issues with any of my lights like this (about 10 of them) i thought they all just operated flawlessly all the time. Im not complaining bout the KR1, I don’t like it any less, and i don’t want to get rid of it. i just figured someone on here could help explain what i clearly did not know. Thanks everyone!