Problem with Fenix TK40

[kwkarth]

I suspect you are not fully aware of how the battery magazine is wired. Both polarities of the battery are available from the springs at the top of the pak.

The current supplied to the led driver is actually from those contacts. The tailswitch is only used to provide "control" pulses to the micro-controller.

Make sure everything is as it should be.

 

[taivox]

delete

 

[tk40notworking]

Hello all,

I am having the same damn problem with my TK40. It is about 2 months old and started to intermittently go on and off, sometime would come back on if it was shaken. It now does not come on at all and I have put new batteries in it. I have also tried cleaning it as FENIX suggests but still it does not work ! I pad $140 and the damn thing does not work after 2 months. I am trying to get the vendor to do something about it, although I bought it off of e-bay, so who knows what will happen.
Has anyone successfully fixed theirs?

 

[tk40notworking]

I am having the same problem with my tk40 and have tried cleaning it, still it does not work. I have changed batteries too.
Any ideas??

 

[djjokki]

I also have problems with my TK40.

It worked fine during the first set of batteries. After a while, it would barely go on, turned itself off again quite fast for a couple of times, and I assumed this was due to low power in the batteries.

After recharging the batteries and trying to turn it on, I get no light from it at all. Have tried two sets of different batteries, none of them will make it work.

Have read through the tread here, checked contacts etc. (Both cleaned them and made sure the four (5 with the spring) contacts are ok, but still I can't get any light from it.
Have also tried shaking it / unscrewing the parts bit fot bit etc. with no luck.

I've also tried pressing the switch a bit harder. I'm not sure how to open the switch to have a look at the spacer here etc.

Does anyone know how to check of the switch is working?

Any other ideas? All answers will be highly appreciated!

JK

 

[Locoboy5150]

Does anyone know how to check of the switch is working?

Remove the tailcap from your TK40. Press down on the fully loaded battery carrier so that it bottoms out and makes full contact against the underside of the head. Take a paper clip or small wire and use it to connect the center, silver colored contact on the bottom of the battery carrier to the threaded portion of the tail cap end of the body tube while still pressing down on the battery carrier so it makes full contact with the head. The silver colored contact is the one on the bottom of the battery carrier that the gold tailcap spring normally touches. If your TK40 is operating normally, it should light up when that contact is made between the bottom of the battery carrier and the threaded part of the body tube. it should remain lit as long as that contact is made.

If your TK40 does light up with the paper clip test, then the head is fine and the contact in your switch is not working. I had that problem with mine. Open the switch by removing the silver retaining ring on the inside of the tailcap. That's the ring with two holes drilled in it 180 degrees from one another. those holes are for a spanner wrench, but I found that a small pair of needle nose pliers worked fine for removing it. Once that retaining ring is removed, then the switch assembly can easily be disassembled. (Note that you'll have to disassemble the switch assembly in the exact same way in order to replace the rubber switch cover when it eventually wears out.)

My switch just needed a few squirts of electrical contact cleaner and then everything worked perfectly once again.

 

[djjokki]

Thank you very much for the quick response and a very good description/advice!

I'll try this today and let you know how it went. :)

JK

 

[djjokki]

Ok, I did some testing now. I'm not able to produce any light from it by following your instructions. Seemes like there may be a problem with the head unfortunately.

I did some measurements with a multimeter, seemes like the switch is working ok.

Think I'll have to contact the store and ask them how to proceed. The guarantee should cover this I think?

Thanks for the advice anyway!

 

[Locoboy5150]

You're welcome and thanks for the update. Please keep us informed on your warranty work. Thankfully, I've never needed to use the Fenix warranty so far but I've always worried about that because they're based in China.

 

[pubdef]

I just today found my TK40 totally dead. Couldn't get it to light by shaking, or anything else. Batteries fine, and no corrosion. Couldn't measure appropriate voltages anywhere, though, and finally figured this:

Take all batteries out of the carrier. MAKE SURE THE CENTER POST IS TIGHT. (The black rod at the center of the carrier; it's hidden when the batteries are loaded.) Mine was loose. I turned it (as if tightening a screw into the bottom of the head of the carrier) and after several turns it became snug. Voila! Let there be light!

Hope this helps anyone having problems with this light...

 

[Kilovolt]

Thanks for the heads up Pudbef, I will check my black rod.


And a warm :welcome:

 

[NathanF]

Anyone else had the problem with a tail button that requires a noticeably harder push than it did when new? Mine just recently started showing that symptom, and it's worrying me. This is my baby!

 

[HKJ]

Anyone else had the problem with a tail button that requires a noticeably harder push than it did when new? Mine just recently started showing that symptom, and it's worrying me. This is my baby!

Try opening the light and listen for escaping gas, it might be a battery that has leaked some gas.

 

[NathanF]

Try opening the light and listen for escaping gas, it might be a battery that has leaked some gas.

I'm afraid I don't understand how that could be to blame. In any event, I heard no such thing when I unscrewed it last night. These are fairly new eneloops as well, not cheapo offbrands.

To me, it feels more like the switch's contact pads are wearing down. This light is fairly new though as well, so it's not like I cycle it on and off 10 times a day or anything.

 

[HKJ]

I'm afraid I don't understand how that could be to blame. In any event, I heard no such thing when I unscrewed it last night. These are fairly new eneloops as well, not cheapo offbrands.

A high gas pressure inside the light can make it hard to press the switch, but it is mostly a problem with alkaline.

 

[Locoboy5150]

To me, it feels more like the switch's contact pads are wearing down. This light is fairly new though as well, so it's not like I cycle it on and off 10 times a day or anything.

You might want to try what I did before to my TK40 and suggested to another member in post number 26 of this thread:

http://www.candlepowerforums.com/vb/showpost.php?p=3306753&postcount=26

After I cleaned up my TK40's switch it has worked flawlessly to this day.

 

[NathanF]

You might want to try what I did before to my TK40 and suggested to another member in post number 26 of this thread:

http://www.candlepowerforums.com/vb/showpost.php?p=3306753&postcount=26

After I cleaned up my TK40's switch it has worked flawlessly to this day.

Thanks for the info - somehow I missed that post. I'll give it a go, and report back. Besides, this is just the excuse I've been waiting for to buy a spanner wrench! ;-)

 

[NathanF]

You might want to try what I did before to my TK40 and suggested to another member in post number 26 of this thread:

http://www.candlepowerforums.com/vb/showpost.php?p=3306753&postcount=26

After I cleaned up my TK40's switch it has worked flawlessly to this day.

So, I took apart the switch assembly without issue, but I wasn't quite sure what to clean. As near as I can tell, the rubber boot is nothing more than a rubber boot - it doesn't have a carbon contact or anything cleanable that would affect switch operation.

The problem, then, is the actual switch itself. Were you able to disassemble the switch and clean it internally? I fiddled with it a bit, but at first glance it does not appear to be able to be opened. I did roll it around a bit and exercise it, but it did not improve operation - it still is possible for the switch to "click" but not actually activate without sufficient pressure.

Here's a poor quality pic of what I'm referring to.

 

[Locoboy5150]

I didn't disassemble that electronic switch any more than what you have shown in the picture. I just squirted some electrical contact cleaner in the bottom of the switch, clicked it on and off a few times, put the whole tail cap back together, and my TK40 worked just perfectly once again.

I squired the contact cleaner at the base of the black plastic cylinder, right where it passes through that silver metal plate.

 

[NathanF]

I didn't disassemble that electronic switch any more than what you have shown in the picture. I just squirted some electrical contact cleaner in the bottom of the switch, clicked it on and off a few times, put the whole tail cap back together, and my TK40 worked just perfectly once again.

I squired the contact cleaner at the base of the black plastic cylinder, right where it passes through that silver metal plate.

Interesting. I'd be a bit weary about putting a liquid (regardless of whether or not it is a non-conductive cleaner) into a switch like that, but if you said it worked, I'll have to give it a try.

What brand contact cleaner did you use?

Thanks for the info!