Fenix TK20 mode switching

Anyone has problem with their tk20 when they first get it out of the package? Mines cannot switch modes.

The mode switch is between the upper bezel and the grooved part that connects to the body. Mines is literally stuck and cannot twist. Hands are sore now trying to twist it loose.

is this normal? I have a feeling that the mode switching should be firm, not torqued in.

I have a feeling that you're trying to twist apart the two halves of the head, not the head and body.

Marduke said:

I have a feeling that you're trying to twist apart the two halves of the head, not the head and body.

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If that's the case, then why is the light brightness constant when I kept removing the bezel?

Something feels a bit odd to me with this flashlight. Fenix's videos and other youtube users twist a little and the light dims or intensifies.

If I just twist the bezel towards losening, it does nothing but flickers

Duracell 1800MaH rechargables used.

What happens when fully tightened? That's the only spot where you get high mode.

Also, remove the head and clean and lube the threads, and clean the contacts on the PCB.

Marduke said:

What happens when fully tightened? That's the only spot where you get high mode.

Also, remove the head and clean and lube the threads, and clean the contacts on the PCB.

Click to expand...

When fully tightened, the beam is fairly bright. When loosening, the beam intensity remain constant.

This just came in today so not too sure if it's necessary to clean it.

Flashlight maintenance 101

Even when new, no matter the brand, ALWAYS clean and lube upon arrival. No exceptions.

are the cells fresh?

Fresh Energizer just put in and clean out with alcohol swab. Lubed it with small amounts of bearing grease and TADA! Nothing happened!

Cleaned pretty much all the treads, battery cap treads and surface, body's conducting surface, bezel's tread, board, conducting surface. Nada. I'll contact Fenix about this tomorrow since it's time to go babysit my nieces and nephews.

Definitely check the capacities of the cells. Or try primaries.

You removed the bezel? the part that holds the lense in? That's the wrong thing to twist. You should be unscrewing the entire head (as though you are going to take it off), to change levels.

Definitely clean it, though.

Just a reminder, the high mode is ONLY when the head is tight. Loosen it at all, and it goes into general mode. Try pointing at a distant target and look at the beam when you do it.

Also, what Energizer are you using? Not Super Heavy Duty I hope....

Marduke said:

Just a reminder, the high mode is ONLY when the head is tight. Loosen it at all, and it goes into general mode. Try pointing at a distant target and look at the beam when you do it.

Also, what Energizer are you using? Not Super Heavy Duty I hope....

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Just did a test comparison with my surefire g2l, ultrafire c308, and this tk20. sadly, the tk20 is too dim and the throw intensity isn't stronger than either. Regardless of the color, it should hurt your eyes at 50ft away--like the g2l and c308--but it doesn't. Is this spec about right for the tk20? is it really a whole lot dimmer less throw than a g2l?

battery used are regular alkaline energizers. Dont have any lithium atm. Kids are currently sleeping so got some time to do some more testings only.

Odd thing about energizers is that when fully twisted, the light dies and when loosened, the light turns on.

RMA it, you are only seeing the low mode.

Marduke said:

RMA it, you are only seeing the low mode.

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I have that same feeling too. I think this one's broken. Fenix wont have any issues with replacements or repairs, do they?

Just to confirm: you have tried a different set of fully charged rechargable cells? If the light dies when in the high position, it sounds like the batteries aren't handling the current draw, or something.

Contact your dealer, and try fresh cells. Also measure cell voltage.

Marduke said:

Contact your dealer, and try fresh cells. Also measure cell voltage.

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Foxx510 said:

Just to confirm: you have tried a different set of fully charged rechargable cells? If the light dies when in the high position, it sounds like the batteries aren't handling the current draw, or something.

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Excellent observation from both of you. Right when I heard about the high mode going dead and Foxx mentioning about current draw, I pulled out the Volt meter. The "Fresh" batteries that came out of the package had low voltage 1 of the 4 batteries had 1.5v...The rest came up to .8-1.1v I guess this is what EP car hobbyists call unmatched cells.

I went ahead and grabbed another used energizer measuring at 1.49v and VOLA! It puts my G2L to shame But G2L still have the better flood

Thnx a bunch. Kudos to Marduke for guiding me through the troubleshooting process.

Now I can finally wrap this light up as a present to my hunting bro.^^

PS> Gotta get me one myself after seeing the real potential of this light.

Tiresius said:

I went ahead and grabbed another used energizer measuring at 1.49v and VOLA! It puts my G2L to shame

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Fenix TK20 kicks ***!

And Marduke kicks *** too... always helping everybody.

dun forget its a good butt plug too .....

Thanks for the comments. Turbo mode on my TK20 stopped working also....

After reading this thread, fresh cells did the trick. :twothumbs

I wish I have a TK20.