Problem with Fenix TK40
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burntoshine
Enlightened
have you tried using a different set of batteries to rule out a battery problem?
also try cleaning the threads. it's tedious, but sometimes i'll get a razor blade, tear off a small piece of a paper towel, fold it over so there's two layers of paper towel and wrap it over the razor blade to get into the grooves of the threads. i also dab some rubbing alcohol on the paper towel. if your threads are dirty enough, they can cause a connection problem.
and you should check the other electrical contacts (the ends of the battery tube and where they connect as well as the contacts in the head); wipe them clean with some alcohol.
check to see if the 4 copper springy contacts on the battery carrier that contact the head are all about even and not smashed down.
make sure the tail cap retainer ring is tight.
hope this helps.
also try cleaning the threads. it's tedious, but sometimes i'll get a razor blade, tear off a small piece of a paper towel, fold it over so there's two layers of paper towel and wrap it over the razor blade to get into the grooves of the threads. i also dab some rubbing alcohol on the paper towel. if your threads are dirty enough, they can cause a connection problem.
and you should check the other electrical contacts (the ends of the battery tube and where they connect as well as the contacts in the head); wipe them clean with some alcohol.
check to see if the 4 copper springy contacts on the battery carrier that contact the head are all about even and not smashed down.
make sure the tail cap retainer ring is tight.
hope this helps.
This is my first post - so hello all.
I've had the same problem with my TK40 since I bought it a month ago. I'm running on eneloops to.
I think I've traced it to the spring contact on the battery carrier. One is soldered on much closer to the outside of the carrier than the rest - which means its contact sits partly on the plastic cover on the battery. I can knock the TK40 off if I give it tap, which is annoying. I will upload an image when I get time. Has yours got the same issue? Has anyone else ecountered this?
I've had the same problem with my TK40 since I bought it a month ago. I'm running on eneloops to.
I think I've traced it to the spring contact on the battery carrier. One is soldered on much closer to the outside of the carrier than the rest - which means its contact sits partly on the plastic cover on the battery. I can knock the TK40 off if I give it tap, which is annoying. I will upload an image when I get time. Has yours got the same issue? Has anyone else ecountered this?
headophile
Enlightened
try unscrewing the head in small increments (1/8 of a turn) till the light turns on and see if that works out.
burntoshine
Enlightened
man, that really sounds like it's just a simple connection problem. the fact that you can get it to turn on by knocking it leads me to believe that it might be the battery carrier.
i always keep my TK40 "locked-out" on the nightstand. one time i was showing my friend (a non-flashoholic) how you lock-out the light. i was explaining to him that you do this when you're not going to use the light for a while because there's a "parasitic drain" caused by the type of switch used. i was pushing the button so show him it wouldn't turn on, but then accidently bumped the bezel and it flashed on for a second.
just thinking about this makes me wonder if you should try bending those 4 gold leaf spring thingys. maybe they're smashed down too far. try bending them upwards more. try getting them about halfway between the top of the center gold spring and the highest plastic piece.
i'll go take a picture of the top of my carrier here in a second...
EDIT:
...are your 4 leaf spring things like this? they may need to be even further up than mine. it's possible you have more distance from tail spring to head contacts on your TK40. who knows; your battery tube could be a millimeter or two longer, or your tailcap retainer ring could be a little tighter, or your tail spring could be a tad shorter or smashed down. there could be one little difference in your light that causes it to work differently. a lot can happen in manufacturing. one thing can be off by a little that causes the light to act differently than designed.
i always keep my TK40 "locked-out" on the nightstand. one time i was showing my friend (a non-flashoholic) how you lock-out the light. i was explaining to him that you do this when you're not going to use the light for a while because there's a "parasitic drain" caused by the type of switch used. i was pushing the button so show him it wouldn't turn on, but then accidently bumped the bezel and it flashed on for a second.
just thinking about this makes me wonder if you should try bending those 4 gold leaf spring thingys. maybe they're smashed down too far. try bending them upwards more. try getting them about halfway between the top of the center gold spring and the highest plastic piece.
i'll go take a picture of the top of my carrier here in a second...
EDIT:
...are your 4 leaf spring things like this? they may need to be even further up than mine. it's possible you have more distance from tail spring to head contacts on your TK40. who knows; your battery tube could be a millimeter or two longer, or your tailcap retainer ring could be a little tighter, or your tail spring could be a tad shorter or smashed down. there could be one little difference in your light that causes it to work differently. a lot can happen in manufacturing. one thing can be off by a little that causes the light to act differently than designed.
Last edited:
headophile
Enlightened
there also could be too much contact or something to that effect.
at first my tk40 won't turn on with the head tightened as far as it can go. i had to loosen it by 1/4 of a full turn to get it to turn on.
now all is fine.
at first my tk40 won't turn on with the head tightened as far as it can go. i had to loosen it by 1/4 of a full turn to get it to turn on.
now all is fine.
burntoshine
Enlightened
BTW, my tail switch/button is a little goofy. i have to press it harder than i used to. it worked perfectly when i first got it, but later it would not always switch modes and turn on and off as desired. then i found i just have to press the button about twice as hard as i was used to and it operates flawlessly now. i just had to get used to pressing it harder.
it started doing this, this past summer, after i took it swimming in a swimming pool. i had it submerged for about two hours while switching modes under water. maybe a tad bit of water seeped into the switch....? :duh2: maybe i should check.
p.s. i don't recommend going swimming like this with any flashlights unless they are specified suitable for diving.
...i was feeling brave that night.
it started doing this, this past summer, after i took it swimming in a swimming pool. i had it submerged for about two hours while switching modes under water. maybe a tad bit of water seeped into the switch....? :duh2: maybe i should check.
p.s. i don't recommend going swimming like this with any flashlights unless they are specified suitable for diving.
...i was feeling brave that night.
burntoshine
Enlightened
good point. maybe in your case, your center spring wasn't making contact.
...i'm no expert.
collo
Newly Enlightened
I had a yearning for one of those orange DX switch rubbers ....
The rubber on the TK40 is deeper than that on previous models. I got around this by using a washer between the rubber and the white plastic spacer fitted to the switch.
The upshot of this is that the switch had to sit closer to the front of the torch by an amount equal to the thickness of the washer. This should not have made any difference apart from the springs on the battery carrier being compressed a bit more, but the switch operation became unreliable. I ended up going back to the original setup, which fixed the problem.
This suggests that the switch height and battery spring positions can be a bit sensitive.
It might be worth unscrewing the switch retaining ring and reseating the switch a couple of times to see if that fixes your problem
The rubber on the TK40 is deeper than that on previous models. I got around this by using a washer between the rubber and the white plastic spacer fitted to the switch.
The upshot of this is that the switch had to sit closer to the front of the torch by an amount equal to the thickness of the washer. This should not have made any difference apart from the springs on the battery carrier being compressed a bit more, but the switch operation became unreliable. I ended up going back to the original setup, which fixed the problem.
This suggests that the switch height and battery spring positions can be a bit sensitive.
It might be worth unscrewing the switch retaining ring and reseating the switch a couple of times to see if that fixes your problem
HKJ
Flashaholic
I believethe white pads was added because some people put the batteries in the wrong way and this is a very bad thing to do on TK40.
Methodically go through and measure the open circuit voltage on each cell to make sure they're all up to snuff, then insert them in the battery carrier. Measure the voltage on the spring contacts for each half of the carrier. Make sure those measurements are appropriate. Once you've done this, you can rule out the battery pack. Then focus on the switch. While the tailcap is removed from the light, measure open and closed resistance across the switch. It is a momentary switch, so it will be closed when depressed, and open when not pressed.
Once you determined that's ok, you can start inspecting/cleaning/lubing your threads, etc...
Good luck!
Once you determined that's ok, you can start inspecting/cleaning/lubing your threads, etc...
Good luck!
Jay611j
Enlightened
I'm having this issue as well. I've tried everything suggested in all the posts and nothing works. It's funny, whenever my light won't come on, it seems to activate if I turn the head slightly OR turn the tailcap OR give it a tap. Any of those seem to work but if I turn it back off for a while and then back on, I need to do one of the above tricks to get it to turn on again. Hopefully someone will come up with a solution. I have stopped using my TK40 because it is so annoying.
