FW3A FW3C FW3T tailcap button mod - o-ring helps but click doesn't always trigger

I have an FW3A, an FW3C, and an FW3T.

I want:

  1. The button to always work when pressed (so that when you feel it click, the light always goes on)
  2. The button to be reasonably hard to press

I modded my FW3C and FW3T the same way (but my FW3C didn't have a retaining ring--maybe that got added later): I removed the nubbin and used a keyboard o-ring (tried two different thicknesses: 0.4mm and 0.2mm).

The FW3T (with the retaining ring) behaves pretty well now: the click is positive and the light comes on.

The FW3C on the other hand: the click feels the same, but getting past the "click" isn't always enough to get it to turn on. Instead, you have to "bottom out" the button firmly past the click. If you don't, the light doesn't turn on.

I really want to like this light. I just need it to work. The original button was so hair triggered it would turn on in my pocket constantly.

Here it is:

FW3C help anyone?

I wish I could . Surprised no one that can , has . Good luck . Oh yeah, nice looking light .

Hey there. Glad to help. Could you show a picture of the oring sitting inside the rubber tailcap? I suspect the oring is too thin and/or off center.

I have a bunch of –008 o-rings I can ship you some for postage

Hey, thanks a ton for the kind offer, Jared!

Let me know if these images are helpful or if you need anything else.

This same ring worked well for the FW3T (which had the retaining ring).

If I need to buy another set of tailcap hardware, I’d be happy to do that.





hmm… My o-rings are 1.82mm thick and there is no slop / pre travel to the switch.
There is nothing that jumps out at me in these photos other than the metal ‘popper’ switch might look slightly different than mine (steeper sides?). Anyway if these orings work in your other samples then maybe the best advice I have to begin troubleshooting is swapping the switch/spring/pcb assemlblies between your lights and see if the behavior follows the pcb or the host.

I haven’t done any o-ring mods so take this suggestion for what it is, just a suggestion.

Try reinstalling the nubbin with the o-ring in place. If it’s too sensitive again then sand down the nubbin so it’s a bit shorter.

I have done this and it is another way to tune the activation pressure and feel of the switch. The dang little nubbin is hard to work with though.

Basically any way that you apply force closer to the center, the required force will be reduced. Secondary effects include the durometer / shape of the interface material.

Thinking out loud… to surpass mucking around with the nubbin - fill the nubbin space with a suitable size dollop of glue or solder (after it has cooled, of course)….?

Only thing i had done different with my original fw3a (it had a retaining ring) was the o-ring i used has a little larger diameter, and it just so happened to be the same exact size as the “hollow” cupped section of the rubber tab that holds the nubbin. When i used my o-ring of that size, i did not use the nubbin.

What i ahd found while trying to fix a fw21 pro tail cap-

The more close to the center of the metal popper your oring/space/nubbin is - the easier the activation of the switch it. The further away from the center of the popper the oring / spacer is the more difficult the activation is, obviosuly.

Meaning - the nubbin is directly in the middle of the metal popper, so it activate very easy.

Using an oring that fills out the whole “dished” section of the rubber does two things -

  1. automatically centers itself around the metal popper
  2. is the largest and furthest it can be from the middle of the metal popper, ultimately making it need the most force to turn on.
  3. it also esnures reliable button activation, as it does not have the ability to “slide” from side to side in the “dish” on the rubber tab piece.

I assume one reason your experiencing unreliable activation with your current oring is becaue it has room (albeit, only a little, but a little matters in such tolerances) to move from side to side in the “dished” section of the rubber tab.

My oring that filled out the dished section completely made for very reliable activation.

I will measure my orings once i find them and report back. It is more about the OD, outside diamter. I bought about 25 10 packs between 10 different hardware stores to find ones that fit right. I think they ended up coming from a multi pack.

As I specified from the beginning, –008 industry size is an exact fit to the rubber boots cavity. It is a 1.8mm thickness which leaves non room or slop in any direction and minimally preloads the popper. I don’t know if anyone has had issues when using this size.

ohh, yea i missed that, i apologize JaredM. Yea based on OPs picture, and all the room he has in the cavity there, thats got to be the issue.

No need to apologize :slight_smile: but i appreciate it anyway.

I’d blame the thickness before the centering, but they both matter. Is there any jiggle /slop to the switch?

A click is a click is a click. By that I mean if it’s clicking then it should be switching. So I suspect that you are looking at a contact issue elsewhere. However, I used an o-ring that I just happen to have hanging around so I didn’t measure it but it fit with just a little bit of play and it definitely sat up proud of the rubber piece that it’s sitting in. The idea of moving the tail cap or switch to different lights should prove everything.

So, how about this?

https://www.amazon.com/008-Neoprene-Ring-Durometer-Round/dp/B0053UU1KG

008 Neoprene O-Ring, 70A Durometer, Round, Black, 3/16” ID, 5/16” OD, 1/16” Width (Pack of 100)

Is that the right size?

Verdict: the problem follows the PCB. I swapped the PCB from the FW3T to the FW3C and the problem followed the PCB to the FW3T. I did not swap the retaining ring (per the above, only the FW3T had a retaining ring: I kept that retaining ring in the FW3T after the swap).

So, what can I do?

Here are some more photos showing which PCB was in which torch originally (before the swap).






I emailed Neal to see if he has spare parts, but I haven’t heard back yet. Any ideas on where to get spare FW3A parts without buying a whole light?

Remove the poppers and inspect under them. To me it seems like the troubled one isn’t touching the center pad reliably. You could put a tiny solder blob on the center pcb pad and likely clear this up. Make sure the popper is taped on nice and centered and there is no debris or flux splatter on any of the contacts or popper. Wiping down with a cotton swab and ipa then deoxit if you have any could help too.

So when is a click not a click? When the clicker is dirty or burned or otherwise fudged up. When you open it please take some good pictures with good lighting before you start cleaning.

What’s the best way to open it up?