Is this normal for a Fenix TK40?

[Bubu]

I noticed something the other night when playing with my Fenix TK40. When the flshlight is on the lower power setting only 3 of the 4 parts of the LED turn on. But when you turn on the next power setting all 4 parts of the LED turn on.


Is this normal for the Fenix TK40?


Low output:

And this is the next level up with all 4 lit up:

 

[Larbo]

I would say that is not normal, all 4 leds light on mine on all power levels, maybe a call to the dealer you purchased it from is in order. Hope this helps.

 

[Gunner12]

That single die might have a much higher Vf then the other dies. I'd ask for a replacement.

Can you check if the same die is dimmer then the other dies on the higher levels?

 

[monkeyboy]

It just means that at this level, the applied voltage is above the threshold required to light three of the dice but it is below that threshold for one die. This is entirely possible with the 4 dice of the MC-E wired in parallel. I'd expect that the dice are well matched at higher drive levels, but this doesn't necessarily mean that this is the case at low drive levels. I saw a previous thread with pictures of MC-E's and/or P7's at low drive levels where the brightness of the dice did not match, but at higher levels they did. (various ND filters and fast exposures were used to capture the images (IIRC) without clipping the highlights)

I guess if it bothers you, you could see if they'll offer a refund but there's nothing fundamentally wrong with the light IMO.

 

[Illum]

That single die might have a much higher Vf then the other dies. I'd ask for a replacement.

I've never heard of CREEs possessing sloppy gate precision :thinking:

 

[Bubu]

Can you check if the same die is dimmer then the other dies on the higher levels?

There is no visible difference in brightness on that one die compared to the rest.

 

[Rexlion]

You got a custom model with extra-low low? Lucky you. :grin2:

 

[Bubu]

Seeing as a die does not work at the low setting does that mean I am using less battery power as opposed to one that works properly at this setting?

 

[Gunner12]

I don't think so, because the driver is probably sending the same amount of power to the LED, so total power consumption is the same (the other 3 dies get more power then normal at that mode).

 

[TranceAddict]

this is the nature of LED, vf will increase and it becomes permanent if the junction temperature exceed safety threshold, on the other hand that particular die is partially burnt, send it for warranty claim.

 

[Wiggle]

I don't think so, because the driver is probably sending the same amount of power to the LED, so total power consumption is the same (the other 3 dies get more power then normal at that mode).

Yeah the Vfs of the dies are slightly imbalanced so the TK40 driver only supplies enough voltage to get the required current for that power level. Since the Vfs aren't the same, one is not even turning on at these low drive levels. Does the beam look funny though?

 

[Bubu]

The beam looks normal until you get close to a falt surface, then you can tell there is something missing. It has bigger black spot and slightly offset to one side.

I e-mailed the online store regarding warranty and I am waiting for a reply.

Does Fenix normally replace the part or could I expect a new TK40?

 

[Locoboy5150]

That's definitely not normal. My TK40 doesn't do that.

 

[droeun]

Damn that sucks!

I checked mine yesterday on low before even reading this thread & they all light up. Definitely take it back.

 

[GSMGuy]

Surely, even if he purchased it from HK, the warranty is worldwide, as they do sell them in th UK - So why can't it either be sent to Fenix UK, or just taken/sent to an authorised Fenix dealer in the UK for warranty work/replacement??

I am sure Fenix would not be bothered who or where the warranty request was made by/from...

Mike

 

[Bubu]

Old thread now...

I actually got mine online from an Australian based store. The TK40 was replaced with a working one. No problems since then.

 

[Locoboy5150]

To check the dies of any MCE LED without going blind, reflect the light in a glass or bucket of water. Then you can clearly see if all 4 dies are working properly at the various light output modes. Another CPF member posted this tip in another thread and it really works.