My new Fenix LD12 gen2 has PWM

Flashlight Dave

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Truthfully I can't notice the PWM either but still not too fond of it being there but I can live with it. As for the clip on the switch I think it is obviously a solution to the assembly not unscrewing itself. I do wonder about the water integrity of the light due to the fact that you can't screw it tight. Just a thought. I had disassembled the switch and that came to mind.
 

Mr Floppy

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Does not do it on high and does not do it on low when you click it off and back on. Strange I know.

I'd definitely send Fenix a bug report. I don't think it is intentional at all. It might be a bit hard to re-program now though
 

Labrador72

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Less lumens? How the LD12G2 is 125 lumens and from what I read on the LD10 it's 100 lumens max.
The LD10 at 100 lumen is very conservative to say the least - Selfbuilt reviews confirmed the LD10 R4 to get 150 lumens and I would expect the LD10 R5 to do even better.
http://www.candlepowerforums.com/vb...-RUNTIMES-BEAMSHOTS-PICS-and-more!&highlight=

When I bought I did a ceiling bounce test which is not very accurate but gives an indication: my LD10 R5 was as bright or brighter than 3 other AA lights ANSI rated between 130 and 150.
The LD10 is likely to be visibly brighter than the LD12 XP-G R5 and S2, not so sure about the XP-G2 LD12 though.

Personally the side switch on the new Fenix for me it has been a deal-breaker but I agree it is a matter of preference. I still really hope Fenix will come out with a new UI for the next round of LD and PD lights.
In any case, the side switch added electronics in the head resulting in a shorter reflector so the LD10 XP-G R5 will throw further than the LD12 R5 and S2. Again, the LD12 XP-G2 R5 is a whole different story.
 

selfbuilt

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Interesting thread.

I would find it highly unlikely that Fenix has suddenly switched to whole different output control mechanism (i.e. PWM). Far more likely is that there is some sort of circuit noise on this sample, that is being intermittently triggered. This can certainly mimic the visual perception of PWM, if the noise is of sufficient intensity and in the visible range.

I have detected many types of circuit noise over the years - but rarely is it visible (i.e., the intensity is generally too low to detect visibly, but not always). I'm afraid all the detection measures used above are simply confirming that that there is a reoccurring signal - not that it is PWM. The only way to confirm PWM is to measure the waveform pattern directly, to see if it is indeed pulse-width duration variable for perceived output.

If you check out the oscilloscope traces in a review like the Klarus XT-11, you will see true PWM waves (i.e., the pulse width increases as the perceived intensity level rises, but pulse frequency remains constant). Whereas if you look at my Nitecore Explorer series round up, you'll see a couple of types of signal noise (neither of which is visually detectable - but it would be if of greater intensity).

In this case, it would appear that you have a defective sample that is displaying significant visual noise/flicker. Personally, I would see about returning it for repair/replacement.

UPDATE OCTOBER 18, 2013: FYI, I've just posted a mini-review of the LD12 - with a thorough oscilloscope examination and discussion of the "flicker" issue here
 
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Flashlight Dave

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Selfbuilt, what you say makes a lot of sense. I would think they only would have switched emitters and reflector and not the electronics and from the way it behaves (especially on low) makes me think you are right that there is a defect. However, appliancejunk reported the same effect making me wonder if maybe Fenix out sourced to a different company or something and that the issue is more wide spread than just mine.
 

selfbuilt

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Selfbuilt, what you say makes a lot of sense. I would think they only would have switched emitters and reflector and not the electronics and from the way it behaves (especially on low) makes me think you are right that there is a defect. However, appliancejunk reported the same effect making me wonder if maybe Fenix out sourced to a different company or something and that the issue is more wide spread than just mine.
Sometimes these sorts of things can be traced back to a batch effect of a specific circuit component. Fenix is a very high volume producer, and it may be one of their suppliers provided something that wasn't consistently within spec. It sometimes only takes one malfunctioning component to cause significant issues, and it isn't always obvious which one (i.e., if only a portion of the supplied components don't function properly/consistently).

Assuming that is the case here, I'm sure Fenix will track down the problem and rectify it shortly (if it hasn't already). But in any case, I would personally return any constant-current light that had a persistent visual flicker.


UPDATE OCTOBER 18, 2013: FYI, I've just posted a mini-review of the LD12 - with a thorough oscilloscope examination and discussion of the "flicker" issue here
 
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Flashlight Dave

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Well I finally got my replacement head and sure enough it has the same PWM like effect. In fact it seems to be in the same frequency as the first. I can only assume it is the way the LD12s are made now. Perhaps it is PWM after all. Anyway, I like the tint on the new head and oddly enough there seems to be a slightly different beam pattern to it. The new head also does not have a serial number. I guess that makes sense if you think about it. As for the PWM like effect I can live with it.

Fenix customer service seems a bit on the weak side. Communication does not seem to be their strong point. I was not sure if they were helping me or blowing me off.
 

Jash

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Yeah, my LD12 has PWM for sure. Low, med and high all show it. Turbo mode is solid. It doesn't really bother me as it's at a very fast rate and under normal use is not so noticeable that it's annoying.

I just figured using PWM was how they got their good runtimes. And the tint on mine is beautiful, pure white. No blue, green, yellow or pink. Just a pure, creamy white.

Yeah baby!
 

Curious_character

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Help me out here. I'm mystified by why so many people seem to equate PWM with cooties. If you have to go through a bunch of gyrations to even detect PWM, what's the big problem with it? It's a good way to get very good efficiency and keep the tint constant with light level output.

I assume all the folks who hate PWM must never use fluorescent lights, which flicker at a rate much slower than typical flashlight PWM.

c_c
 

Labrador72

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I'm even more mystified by why prople who see PWMon their lights don't write Fenix to find out whether what they see is supposed to be there (keep the light) or is not supposed to be there (get light replaced).

Sent from my ST27i using Tapatalk 2
 

Mark Mc

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I don't know if this is a sign of PWM or not, but I noticed the other night when i shined the light on an exposed high speed computer cooling fan while cycling through the levels on my LD12-R5 that the blades on the fan appeared to stop during one of the two middle settings. At the time I thought it odd but that effect would be caused by the light rapidly cycling on and off. None of my other Fenix lights do this.
 

kj2

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I don't know if this is a sign of PWM or not, but I noticed the other night when i shined the light on an exposed high speed computer cooling fan while cycling through the levels on my LD12-R5 that the blades on the fan appeared to stop during one of the two middle settings. At the time I thought it odd but that effect would be caused by the light rapidly cycling on and off. None of my other Fenix lights do this.

I always do the "shower-test" to see if the light has PWM :)
 

sackless

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Mine has this problem too :(

Fenix's standards really are slipping. My LD12 G2 not only suffers from PWM syndrome but also blue-tint-itis and a bad case of ringy-beam. You'd think Fenix would have fixed this by now (or at least recognised it as a problem).

Looks like they've lost a loyal customer.
 

Wiggle

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PWM isn't all bad and I prefer it some scenarios. But to slip it in suddenly into an estasblished model just out of nowhere like this doesn't inspire alot of confidence. Fenix lights (well this model anyway) aren't what I would call a budget light either where it is more excusable.
 

IClight

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I agree, PWM isn't a deal breaker for me either, especially if it's high frequency PWM that I know I won't detect by eye. It is odd however to find in a light when you don't suspect it, and the light isn't known for displaying PWM characteristics.

It's a bit surprising the PWM appears to go away after "restarting" the light, that almost seems like a firmware issue.. Did you happen to mention what battery you are running in this light?
 

sackless

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Fenix lights (well this model anyway) aren't what I would call a budget light either where it is more excusable.

Couldn't agree more. If i'd bought an E series light I would have been a bit annoyed, but not furious. On an LD series though.....

I also just emailed 'Fenixlight.com' (I assume that's the official site) and they sent me an automated reply to say that they are on holiday with SPELLING MISTAKES and GRAMATICAL ERRORS! I am really getting quite pi***d off now.
 

sackless

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I also emailed another Fenix site (fenixlighting), which probably isn't the official site but hey; I've got nothing to lose.
Here's what they said:

Screenshot%20from%202013-09-20%2014%3A53%3A54.png


What does PWM stand for!? Jesus christ!
 

reppans

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What does PWM stand for!? Jesus christ!

Pulse Width Modulation.

Even high frequency PWM is a deal breaker for me now (damn these enthusiast forums). I've unfortunately learned the common everyday instance where you can easily see the HF PWM with the naked eye and it now annoys me. To think I used to use low frequency PWM for years with Black Diamond and Petzl headlamps.... and never noticed a thing (ignorance is bliss).
 
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