Known issue with Arc4: pulsating on level 1

We have verified that about 1 out of 6 (17%) of the newer Arc4s pulsate at about 1hz when level 1 is selected. We detected the problem this morning and have begun work on possible solutions.

Some rev2 and some rev1 units could be affected. The symptom seems to occur when level 1 is selected and the light is used at that setting for longer than a few seconds. The change in brightness is slight in some cases and hard to see while other cases are more pronounced.

So far, we have received 3 complaints out of hundreds of units shipped but I assume that more units than this are effected. If the light is used as recommend (primary set at about level 4), some people may not see it. However, the lights are still flawed and should be replaced.

The pulsating is only visible at level 1. Pulsating at other levels has not been observed.

The pulsating occurs within a matter of seconds of the light being turned on. Heat, run time, battery type does not change the effect.

We have added yet another test to our QC procedure. I again apologize for releasing a defective product.


The Arc4 is a radical development in flashlight technology. It was first released earlier this year. About a month ago, we made a major revision to the design. This has further complicated our ability to account for every possible variation in performance.

But enough excuses, the Arc4 has a lifetime warranty. If your Arc4 is effected in any way by any kind of defect, please let us replace it. For warranty service please email [email protected]

Thank you.

Peter Gransee
Arc Flashlight

Great customer service as ever /ubbthreads/images/graemlins/thumbsup.gif

Just a small bump in the road to the perfect flashlight, we're all on the journey with you Peter /ubbthreads/images/graemlins/smile.gif

Gadzooks Boy Wonder!

No vendor I work with admits a problem unless forced by the CPSA.

I anxiously await the arrival of my Arc4+. I have only owned an LS and am very pleased with the light. The Arc4 will be a step up, and the + is supposed to be on a higher plain.

Hope it arrives before my trip to Europe that begins in about 28 days. /ubbthreads/images/graemlins/poke2.gif

I just checked my Rev2 this morning and it does pulse at level 1, but it's so slight that I wasn't sure if it was the light pulsating or my heart beating. It doesn't bother me though, and would only return it if the pulse got worse. Thanks again for the heads up Peter!

Nitnos

Peter,

I returned my ARC4+rev2 to you, and it had the pulsating level 1 problem and a batterie rattle problem too /ubbthreads/images/graemlins/smile.gif
If this help you, when I have put the rev2 head to the rev1 body, I haven't see this pulsating on level 1 /ubbthreads/images/graemlins/smile.gif

Maybe a body rev2 problem ?

I have the pulse on my Rev2. It is pretty minor. Just to make sure level 1 is the bright setting, correct? That is when I notice it. I'll e-mail you Peter.

Thanks for keeping us informed! /ubbthreads/images/graemlins/thumbsup.gif

peter, any idea what's causing this problem?

I do Roth. Can I keep it to myself? A competitor might benefit from this information if I were to post.

I love being open with you guys but recently it came back to bite me in the butt.

Needless to say, we know how to detect it and we have a fix. All that is left is to me to apoligize once again for having a problem in the first place.

Peter

oh, i suppose /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/twakfl.gif /ubbthreads/images/graemlins/tongue.gif

PG: But could you tell us if it is due to any safety mechanism jumping in?
That means, does it say that something is overheated or so?
And Arc4s which have this sympton should not be used on this level?

So far, I have not seen any evidence that the light will be damaged by prolonged running with this defect. I have observed at least one that simply shut off after a while but it then worked again the next time it was turned on.

Peter

Thanks Peter!

/ubbthreads/images/graemlins/thumbsup.gif

My Arc4 has a slight flicker, even at level 4. Unfortunately, I just got my Arc4 back for the fix on the tail switch on 4/30, the day that Peter posted the notice about the known flicker problem. It looks like I'll be sending it back again next week. /ubbthreads/images/graemlins/frown.gif

asdalton, How much easier is the switch to operate after getting it back from arc? Does the switch operate with a light tactile feel?

Before sending back, would you insert a conductive .033-.066in spacer (aluminum foil folded up or copper washer) between the end of batt and gold disc.

I'm dying to know if this fixes your flicker problems.

Compared to my temporary foil fix, the fixed switch has a much softer feel, which is a lot nicer. There seems to have been a pad or spring inserted between the plunger and the external rubber button.

I'm not even going to try that washer fix for the flicker problem. It is clearly an issue with the electronics rather then the electrical connectivity to the battery.

[ QUOTE ]
asdalton said:
Compared to my temporary foil fix, the fixed switch has a much softer feel, which is a lot nicer. There seems to have been a pad or spring inserted between the plunger and the external rubber button.

I'm not even going to try that washer fix for the flicker problem. It is clearly an issue with the electronics rather then the electrical connectivity to the battery.

[/ QUOTE ]

Not necessarily. Additional resistance from the battery to the converter can limit the maximum current/voltage to the converter, requiring additional draw, which can cause converters to pulsate as they hit their current protection limits for the MOSFETs. This can manifest itself in a wide variety of ways to the user, depending on the design, topology, and whether a type 1, type 2, or type III feedback compensation loop is utilized (or the compensation that is used in software).

Peter, you should have received my 4+ for the switch repair on Friday. Would you please check it to see if it also has the flicker problem? I did not use it enough to find out if it flickered before sending it back. I would hate to have to re-send it.

Thanks,
Rick del Monte

[ QUOTE ]
asdalton said:
Compared to my temporary foil fix, the fixed switch has a much softer feel, which is a lot nicer. There seems to have been a pad or spring inserted between the plunger and the external rubber button.

I'm not even going to try that washer fix for the flicker problem. It is clearly an issue with the electronics rather then the electrical connectivity to the battery.

[/ QUOTE ]
Pic's please... it seems Arc has elected to lengthen the plunger by placing a pad on top of the plunger.

This of course fixes the hard switch problem. Please note the 12.5 thousands thick disc still has to deform .080 just reach the battery base, then has to go another .050 to operate switch. This is almost at rupture point of the gold disc.

But that's not the issue here. Newbie just pointed out that if the contact is not made solid enough and there is resistance limiting maximum current/voltage to the converter, this could possibly lead to flickering.

The cone spring is at it's limits pushing the gold disc aginst the battery.

this is the reason I requested that you try inserting a conductive spacer between the battery and gold disc. Also you could try stretching the spring further causing the spring to press harder against the battery.

Hey it doesn't hurt to trouble shoot. It may save a trip back to Arc, if simply scretching out the spring fixes you problem.

[ QUOTE ]
cy said:
This of course fixes the hard switch problem. Please note the 12.5 thousands thick disc still has to deform .080 just reach the battery base, then has to go another .050 to operate switch. This is almost at rupture point of the gold disc.


[/ QUOTE ]

You keep writing this, but what is your evidence? If the disc were actually near its rupture point, it would have entered the region of plastic (permanent) deformation with the first press of the switch. (See this link.) This means that it wouldn't spring back into place for the second press. This is clearly not the case.

Also, there is plenty of evidence that the pulsation problem has nothing to do with the electrical contact with the battery. First, there is the fact that another user (jeryray) tried your fix, and it had no effect on the flicker. Second, there is the fact that Peter wrote about replacing the flickering lights, not tweaking the tailswitch. And third, there is the fact that the flickering is not affected by battery type or runtime.

And anyway, I'm returning the light because I shouldn't have to settle for a homemade fix on a light that should be expected to simply work.