Have you tried stripping and reassembly? See if it can be better centred? It looks like its not seated right.
gords1001, yes I did disassemble the tailcap. The switch is cut too small, this is the best centering I could manage. It works but the boot cap is off to one side too. I gave the light to my son, he doesn’t care or notices it. Other than the switch the body is flawless. Very nice output and I really like the 2 mode groups. I never had a light with different mode groups.
You can get some rubber switch thingy (what´s the actual name of the rubber parts?) that have some extrsion on th inner side so it hits the actual switch earlier/making it longer/shortening the way to get a click. And you can center the switch quite easily by not screwing the brass ring completely, adjusting the switch and tightenng the rass ring now. That worked here very well 15 minutes ago ; )
Is this the smallest 18650 flashlight on the market? It’s tiny!
The smallest 18650 EDC light would be a twisty.
The PAlight V60 for example, a defacto twisty 18650 EDC according to the following thread
Here’s the switch, top section cut more than the bottom.
Hm, mine looks indeed more symmetrical.
I shoved some rubber foam to take up the space. Better than nothing.
You could resolder the switch on the board to better locate it.
I do think Cngq carries switches pre mounted on boards which may be suitable.
The switch on mine has little legs folded under its self. This meant the switch seemed uneven. I trimed off the extra till it sat flat on the board. Put a single spot of glue under the switch and centered it on the board. Then soldered the legs to the pads on the board.
Centred and solid now. Was thinking about trimming the nubbin on the inside of the boot to flatten the button a bit
I don’t think it’s the switch …I think it’s the tang under the center of the tailcap …
I took out the green glow in the dark tailcap on mine and put in a red one and a lt blue glow in the dark one in another ....if the piece in the silicone tailcap isn't long enough it won't hit the button and will be all squishy feeling .. if you add a o ring or a washer to get these to tailstand then the problem is magnified ..I have some lt blue caps coming from fasttech so we'll see if that solves the problem.
The switch on the small board keeps going off centre in the brass holder. So……
I have used a switch from an old Fenix L2D which with a small amount of filing fits into the brass screw in ring and the silver washer fits over the circular switch housing. It all fits in nicely and the switch feels more robust than the original.
Have seen no issues with power through the switch.
To all of you!
Read the damn review! 
Just kidding, I know you probably bought it before I did and made the review.
If it’s a high pitched PVM noise, then it’s from the driver PVM no low and mainly medium mode. Nothing on High mode. Relube and tighten the pills and body. Solves this easily. Use electrically conductive silicone if possible.
It’s your first light hey? First Nanjg 105C?
You silly, it’s 2 groups, 5/50/100%, 5/50/100%/FastStrobe/SOS.
Not 15%. The other 105C 4 group version is:
Connect the 2nd star from the left to ground: 3-mode: Lo (5) > Hi (100) > Strobe
Connect the 3rd star from the left to ground: 3-mode: Lo (5) > Mid (30) > Hi (100%)
Connect the 4th star from the left to ground: 2-mode: Lo (10) > Hi (100)
Default (shorting no star): 5-mode: Lo (5) > Mid (30) > Hi (100%) > Strobe > SOS
This is by default a memory after on driver that means that the memory kicks in after about 2s. That’s why you have to reset the timer and then switch the light with a second click in under 2s.
Yes, because FF version is a piece of crap when it comes to the tail and nobody before my review cared much to say 
Read it!
You bought a 1A tint, you got a 1A blueish tint that you ordered. I got a 3C yellowish.
Yes, read and then buy
My problems with the tail and it’s switch.
Review.
Tail.
Boot.
Switch.
Anybody interested in a spare switches, alone or on a board without a spring, or even with a spring?
Since I might have overheated my switch due to being impatient a little and might buy a whole pack of new. Anybody interested in a GB? Please post in my review, I check it or PM me. So I know how big the interest would be like!
You can see how I repaired the switch to make it tailstand and also screw the tail as much as possible with the body. Removed the metal ring and redesigned the assembly with a hot glue gun 
Switch board from FF is for a AA light = 15mm not 17mm, that means you won’t center it in the brass tail ring.
A request? Heh, I did not bother to complain to them. Since they sold it functional and nothing else matters to sellers. Yes check my other threads you can get the switches at several shops, but I will probably be making my own since it’s cheaper then buying the whole assembly from intl-outdoor.
Or as I said, get 3-4 people interested and I can make the switches on 0.9mm boards, with or without a spring, low GITD green boot included, GITD green O-ring for the lens also an option, really depends on what people want and pay.
Switches from CNQG, boards from IO, springs if needed from who ever has the suitable and cheapest ones, boots I already have from KD along with GITD O-rings for the leans. Shipping who knows, $2 envelope.
I still think it’s a good light I will be getting a second one probably and putting a Nichia 219 in it. But I don’t want that silly small switch PCB board again! I don’t want to etch my own again…
Or I just may, because it’s cheaper than buying the boards and my custom boards fit flush and centered.
And please, go ask FastTech to list the host for X-Power = D4 = Xiaozhi 0:)
I want the host they use with the correct switch and boot XD
Well the switch board is enough for me, I got enough boots.
Tailcaps from FT are all 7.5mm high, which is too much, you need a 6mm one to tailstand.
Plus blue ones from FT are 16mm not 14mm so they won’t fit.
I disassembled my Xiaozhi because it was flickering. one of the bend metal parts of the switch weren´t soldered properly to the… green… thing. I fixed it.
Unfortunately, the switch doen´s do what it is supposed to. Getting all parts togetehr, the light is always on. I can´t turn it of by pressing the switch.
I guess I did not re-assemble the parts of the switch correctly.
I need some help here.
Where that switch is soldered on each end to the board is very tight - one you want to make contact with the tube and board ground, the other end must not touch the tube, or the board ground. If you touched up the solder on that side, maybe it's grounding out now, resulting in completing the circuit all the time. I've had this problem before, from what I recall, not sure what light.
Argh, I can´t get it working.
It keeps turning on when I turn the tubes down. Itls like a twisty now.