Importance of the foam retainer in the Arc AAA

lately i recall reading some posts here describing problems with the arc AAA, wherein the light flickers when turned on, or refuses to light up when turned on. my first arc AAA was a black HA v3.1, which i've since given to my mum and it started exhibiting the exact same problem, which got worse with time.

i thought it might have been a problem with the roll crimp, but threading the head onto another arc AAA and hot-wiring it to a battery with some wire showed that there was no problems with the head whatsoever. i tried cleaning the -ve contact at the bottom of the battery tube and the threads of both the head and battery tube, but the problem persisted. i got frustrated, so i ripped off the foam retainer and was about to use a screwdriver to put some kinks into the edge of the head (to make contact with the pcb), when i remembered i'd earlier concluded that it was not a problem with the head. since the foam retainer was in bits, i stuck a new one that i'd recently gotten from arc onto it, and reassembled the light. after a few on-off cycles, the light worked flawlessly, as good as new.

the original foam retainer i'd gotten with that arc AAA was thick, but made of a flimsy material that fell apart within a few months of use, which i replaced with some that arc sent me a few months ago. those were made of a stronger and firmer, but thinner material. because the foam was thinner, it did not make contact with the battery in the off position, thus it did not scrape the -ve end of the battery on the -ve contact, and overtime oxidisation must have built up on the contact, which a pencil eraser would have been incapable of removing. the newest foam retainers i got from arc were made of a strong and firm material, that was also very thick and i'm guessing this was what fixed the problem with that arc AAA /ubbthreads/images/graemlins/smile.gif

so for those who have been experience similar problems, whereby the light flickers or refuses to turn on and no amount of cleaning or roll-crimping will solve the problem, get some of the newer foam retainers from arc and that should fix the problem /ubbthreads/images/graemlins/thumbsup.gif

I had the same problem, and Peter is supposed to be sending me a new retainer. I notice that on my new AAA the + contact looks a bit different than the one on the old AAA. The old one has a kind of flat looking contact point, and the newer one has a sort of convex one that sticks up within the retainer a bit. I'm wondering if anyone knows if maybe the older one (flat contact) is somehow "wrong?" Maybe the retainer is not the problem, but it is instead the contact surface? Can anybody compare a couple AAAs and let me know if the forward contact points are flat or slightly bulgy?

Thanks.

chamenos,
Glad yours works again. So the foam turns the battery and cleans the contact? I guess that makes sense.

Does your light have the gold tint "chemkote" finish inside the battery tube. It's supposed to inhibit oxidation.
Another way to clean the negative contact is to glue or tape a tiny piece of fine sandpaper to the end of the pencil and twirl it against the bottom of the tube.

Though I haven't tried it yet, maybe a dab of "de-oxit" or some other anti-aluminum-oxidant would also work.

xrayzebra,
I checked 6 of mine, all new, and the shape varies a bit. Some of the blobs are flat and others were convex. The positive contact is actually a solder blob, not a machined button like on the LS series. I assume that they are done by hand. I don't think one shape is better/worse than the other.

The other thing to consider is, since it is solder, over time, with repeated use, it will flatten down and wear away slowly. That could also account for your old one's contact being flat.

Also, the small gap between the head and body is there to allow the light to keep working as the blob wears down, without eventually bottoming out. (The other reason is to accomodate slight battery length differences.)

Gyverpete,

Good points! You make a lot of sense. Now I know what that small gap is for i.e. as the solder 'blob' slowly wears down, the head moves further into the body to compensate. Not over-tightening the head (to activate the LED) will surely then prolong the life of the solder 'blob' and overall longevity of the light itself.

I seem to remember Peter Gransee saying that it is sufficient to turn the head only until the LED activates..and no more.

Makes sense to me /ubbthreads/images/graemlins/thumbsup.gif
Now I have to make sure no heavy handed oik ever messes with my aaa /ubbthreads/images/graemlins/grin.gif

tardis, Thanks for the compliment. /ubbthreads/images/graemlins/smile.gif

Your right. There is no need to overtighten the head. I give it a light twist, and it has never shut off by itself. The battery doesn't get crushed at all. It has also never turned on accidentally. The foam and o-ring help keep it in whatever position you put it in, whether on or off, by friction.

Same goes for the LS w/twisty pack.

As a side note, my AAA was a bit too tight to turn when new, even with lube, and not wanting to wait for the o-ring to wear-in, I took off the o-ring, slipped it onto a sharpie marker, rubbed it evenly against some fine sandpaper, put it back on, relubed, and it's very smooth and easy to turn one-handed, yet snug enough to perform as described above. This also prevents overtightening because it is easier to tell, by feel, that you've tightened it just enough.

Sorry chamenos, I went a bit off topic. Couldn't help myself. I tend to wander. /ubbthreads/images/graemlins/icon3.gif

gyverpete: don't worry about it! the arc AAA i fixed had a chemkote interior, but i'm guessing the battery must have scrapped it off with use, and when i changed the retainer to the thinner one, oxidisation was allowed to build up on the exposed alumnium. in any case it works like new now, and i have newfound confidence in all my arc AAAs /ubbthreads/images/graemlins/smile.gif just thought i'd mention it since some people were posting about arc AAAs that just couldn't be fixed for some reason.