Fenix TKUE18 post mortem/autopsyl, fatal design flaw?

DayofReckoning

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Re: Fenix TKUE 2018 dissapointment, then joy :) this thing is bright

Being as though I ordered one of these a few weeks ago, and have been waiting on backorder, this thread seriously concerns me. I went with the TK35 due to it's reputation of reliability and robustness.

I wonder why all previous versions of this light had no issues, but now issues are popping up with this version?
 

Richard_T

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Re: Fenix TKUE 2018 dissapointment, then joy :) this thing is bright

Where have you ordered from? official dealer, Amazon? Ebay?
 

Richard_T

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Re: Fenix TKUE 2018 dissapointment, then joy :) this thing is bright

Fenix got back to me about the fault, and said this
"Sorry to hear that your TK35UE 2018 encounters problem .

Where are you reside in now ,Germany ? if yes ,I will ask our local distributor to help you out .

The torch was ordered from Amazon UK, and has now gone back for a refund, third attempt from the UK dealer, if this develops a fault then thats it, back for a refund, and look at something else
 
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DayofReckoning

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Re: Fenix TKUE 2018 dissapointment, then joy :) this thing is bright

Well, as excited as I was for owning this light, sadly I have canceled my order for it. The reports that have been made are completely unacceptable, especially for a light known for it's robustness and reliability.
 

Richard_T

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Re: Fenix TKUE 2018 dissapointment, then joy :) this thing is bright

out of interest what would you be looking at as an alternative?
 

DayofReckoning

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Re: Fenix TKUE 2018 dissapointment, then joy :) this thing is bright

out of interest what would you be looking at as an alternative?

Not really sure at this time. I may just use the funds to buy a Malkoff of some type. At least I know I would be getting a solid, dependable product.
 

Richard_T

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Re: Fenix TKUE 2018 dissapointment, then joy :) this thing is bright

So unit 3 arrived, this time from an official UK fenix distributor, Unlike unit number 2, this one shows as being intended for the UK.
Unlike the first one, this one didnt fall apart when removing the battery caddy, no loose springs, ball bearings or any other bits.
Unlike the Second one, after being on charge for a while ( via the USB socket on the caddy) there is no sign of any additional heat, the caddy is still cool to touch, and the light is a constant red to indicate charging, which is unlike the second unit where the red light flickered as the caddy got warmer ( and started to smell of burning)


Time will tell, this weekend will see its first real world test
 

DayofReckoning

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Re: Fenix TKUE 2018 dissapointment, then joy :) this thing is bright

Glad to hear this one is working ok so far. I hope it stays that way. Please keep us updated.
 

Richard_T

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

The red charging LED has just gone to green, no signs of any flickering, and no signs of any heat or burning smells ( is torch sniffing a thing??)
One thing that did cause a brief bit of concern was a slight rattle when the body is shook without the battery caddy, but this is a little spacer in the rubber tailswitch which appears to be another difference:
the spacer fits neatly onto/over the switch on the battery caddy, Unit 2 ( that failed with a burning smell) didnt appear to have this, Unit 1, i dont know if it did, or didnt as it fell to bits upon opening.

This weekend i wont be the only one out camping with a new torch, its going to be up against a 16 LED thing bought from a DIY store, and a 1 million candlepower something or other, with 37 LEds all arranged like a shower head, on a yellow square body stuffed with D cells ( 8 of the things)
 

DayofReckoning

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

I was looking at the Fenix Worldwide Facebook page earlier, and low and behold the very first review on the page says

"Thank you Fenix after-sale service support for fixing my Tk35 in two occasions"

So disapointing. Even if one were to get a good working sample of this light, I'm afraid that my OCD would constantly be worrying that it could fail at any time. Here's to hoping the OP's light continutes to work good.
 

tom-

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

ditto, am very interested in learning how it goes also.

What I did not know is that the new 35 has a troubled history, think I will hold off also.
 

DayofReckoning

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

Any updates on how the TK35 is holding up?
 

Richard_T

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

update on how it's holding up ?
It isn't, just fell apart, same issue mode selection button falls off, suspected issue, screw thread holding it together is too fine, and it has a fatal design flaw.
Now I'm out camping with nothing but a phone torch, great.
just emailed the distributor, will phone them as well later.
 

Richard_T

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

any ideas on an alternative? I bought some 18650 cells for it, so would be looking for 3,000 lumen+ and similar size
 

Richard_T

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

Now Im back in civilisation for a little while, time for a post mortem report, below ( if it works) is a picture of the switch, the part that fell apart was the Functional switch

... hotlinked image removed ...

The centre part of this features a clear transparent section that allows a battery level LED light located on the battery caddy inside to shine through this shows for a few seconds when you turn the torch on: green constant=full, green flash=part charge, red = almost empty, red flash = low.
This has a ( aluminium) bezel holding it in place ( this is screwed onto the spindle section) underneath the bezel is a spring that allows this part to function as a switch.
Below is the failed switch assembly that fell apart:
IMG_20180729_132235_1.jpg


On the left hand site, you can see the functional switch, this has a white clear section on the left ( presumably to gather light form the charge status LED on the caddy) this then tapers down to the shaft section that goes through the rear part of the torch, providing a waterproof seal is an o ring, and at the end are the remains of a very fine screw thread in the spindle, if you look carefully you will notice that the thread form is heavily rounded on the top ( stripped) this tiny bit of fine screwthread is all that holds the whole thing together
in the centre is the aluminium ring section/retaining bezel, that screws onto the functional switch main body/shaft, this has a very fine thread (in aluminium) that screws onto the very fine screw thread on the spindle.
above is the switch spring, and to the right the mode select switch ( lock off/outdoor mode/tactical mode)

All that is holding this together is a very small section of extremely fine screw thread on the spindle with a small mount of very fine thread in an aluminium retaining bezel.
If you have ever worked with fine screw threads, then you will be well aware of the issues that you will run into, and this is a primary function switch that will get used frequently cycling through the brightness levels.

This is a major point of weakness, and the only workaround would be a re-design of the switch unit, possibly moving the indicator light shine through section ( the clear bit in the middle) from the switch, and replacing fine threaded section with something more durable, there could also be long term issues with the O-ring which will wear after time, making the long term waterproofing of this product impossible, as this component is inaccessible

So now the hunt is on for a replacement, something the same size/form factor ( 2x 18650 side by side) and the same brightness
 
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seery

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

This [from the Fenix website] used to be spot on.

"When a tank is needed, the Fenix TK Series is a must have. Built to take the abuse of daily deployment...toughness...for harsh environments...zero compromise."

But sadly, the TK [series] lights are no longer built to the high standards they once were.
 

Richard_T

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

The most irritating thing, is the TK35UE is an amazing bit of kit, in my opinion it feels good in the hand, has a good runtime, is suitably compact and so on.
Its just got that one major flaw - the switch you will use the most is held together with a tiny bit of very fine thread, just one seemingly minor flaw destroys the whole thing.

As it is I'm awaiting return / refund instructions from the retailer, https://www.fenixtorch.co.uk/ after that its back to looking at what's available, I may buy another fenix, i may even buy another TK35UE- if and only if they re-design the switch.
But for now i have no requirement for a decent torch in the next few months, so it will be refund and wait before i buy again
 

18650

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

The most irritating thing, is the TK35UE is an amazing bit of kit, in my opinion it feels good in the hand, has a good runtime, is suitably compact and so on. Its just got that one major flaw - the switch you will use the most is held together with a tiny bit of very fine thread, just one seemingly minor flaw destroys the whole thing. As it is I'm awaiting return / refund instructions from the retailer, https://www.fenixtorch.co.uk/ after that its back to looking at what's available, I may buy another fenix, i may even buy another TK35UE- if and only if they re-design the switch. But for now i have no requirement for a decent torch in the next few months, so it will be refund and wait before i buy again
What a shame that a redesigned switch has created new problems. My 2014 model is still chugging along and you'd have to pry it from my corpse to get it.
 

Richard_T

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Re: Fenix TKUE18 dissapointment then joy then buring smell, third time lucky?

Posted it off just now, fenixtorch.co.uk have offered to refund postage via paypal, ive only used paypal to pay for things and thats very infrequent ( so much so i cant remmeber my paypal log in/details and my bank/card details have changed since I last used it)
a few more thoughts..

It was the perfect torch, for me, the size was not too big, not too small, runtime was respectable, while i had it running before it disintegrated, the battery's held up well, I even planned on getting two more 18650's, i had already purchased an external 18650 charger. It was bright when it need to be bright, and the bottom two brightness levels were also just right to see what was needed without killing my night vision.
the third brightness level caused a surprise reaction of "how bright - that torch is seriously bright" and that was only 350lumen ( i think) - if i post the reaction from the turbo mode, it will be most likely be censored.

Everything seemed absolutely perfect, then on the fourth evening of an eight day trip i noticed the button seemed a little loose, taped it again to change brightness and then though uh-oh not again, as the switch separated out, fortunately when this happened i was in a location where i was able to scoop up the bits, inside my tent.

I put the previous issues down to bad luck, however this final failure was the last straw. My daytime job is in the engineering/manufacture industry I work with machinery that puts screw threads on things ( lathes/drills/mills etc) on various materials ( metals - stainless of various grades/alu/steel/brass/plastics etc etc.
If a customer wants a part making, and that part was similar to the design of the switch assembly in the TK35UE the customer would be warned that a fine thread over a short distance on a button that is likely to see high usage is a potential Fairlie point with a high risk of failure.

The best way forward would be to ditch the design as it is, replace the transparent section that allows the battery status LED to shine through with solid, hve the top of the switch as a T section and put a sronger thread on the bottom of the T which in turn would be screwed into the base part, and secured with adhesive ( ie loctite high performance thread locker 216) the carry through for the ED battery level should be then moved to a separate location, possibly between the two switches

heres a review form google, lined to previously https://www.google.co.uk/shopping/p...ved=0ahUKEwi7we-Ol9HcAhUJWhoKHSpwD_cQn08IJCgI
FIRST REVIEW REMOVED BY FENIX, SO HERE IS A SECOND – 30 March 2018
– Review provided by
fenix-store.com_fav.png
fenix-store.com30 March 2018

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I purchased the 2018 "Ultimate Edition" TK35. After removing "flashlight" from the box and removing the head to install the batteries, the entire mode selector assembly dropped onto the floor. If you were wondering what those parts consisted of, I shall enlighten you. There is two small springs, 2 tiny ball bearings, two small plastic rings and the selector knob. TOTAL FAIL. I cannot give the product 0 stars because the post will not let you. A product that fails to work out of the box deserves 0 stars not a star. Not to mention, the post being removed as it was there last night, and today it is gone. So, if I could give you a negative star, you just got it. If this review gets removed, I will follow up with posts on every other social media site for your apparent shady behavior.


So thats it, the end, posted back to https://www.fenixtorch.co.uk/ just about to email them with the postage details (£8.60) and the search for a replacement continues, if they re-design the switch assembly then i may try another TK35UE 2018 ( revision b?) but for now the seach continues, and my two 18650's will have to go into storage as i have nothing else to use them with
 
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