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

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?

Mine is just held down with the kapton tape. Just lift one side. But before you do that I would manipulate the switch with a ballpoint pen or other sharp object and then again with a flat metal ruler on it’s side or something with the o-ring in place to see if it’s going straight down. An o-ring that can’t get off center probably is a better choice.

Thanks.

https://www.amazon.com/008-Neoprene-Ring-Durometer-Round/dp/B0053UU1KG(link is external)

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?

Yes

I use 2 washers with glue. Is little more hard clicky but less wobble

If I open it up and end up needing a replacement, any ideas on where to get spare FW3A parts without buying a whole light?

I would also consider buying a whole light and getting an extra tail cap PCB for a few bucks extra.

I don’t think anything is going to need replaced. Slight tweaking should fix this

Here it is opened up. Looks clean to me.



I do have CRC 05103 QD Electronic Cleaner –11 Wt Oz

I could spray that on it.

Is that a good idea?

There actually are some splatter/ spot marks of some kind on there in the ‘bullseye’ position of the pcb. The electronics cleaner is fine but rubbing alcohol on a cotton swab + elbow grease is better. Clean both the underside of the popper in a twisting or ‘lapping’ motion with the swabs and ensure before reassembly that there arent any cotton fibers hanging around under there.

After I clean it with alcohol, should I apply a film of anything? Or just leave it completely bare?

Clean and dry.

Cleaned it with 99.9% and replaced the o-ring with the 008 size. Light is happy and so am I.

A big THANK YOU to all!

And the problem is back. Unless I press dead-center with just the right pressure, it won’t toggle.

I just want to order a replacement PCB at this point to try that. Can anyone help me find out where to buy one?

Do you have a soldering iron?

Yes, and I’m OK with it. Not a master, but I’ve done several hundred small connections.

What should I do with the soldering iron?

I think the aswer might be in post #9 and #18

I hope you figure something out

These switches are very simple. They consist of a flat plastic pcb, a flexible springy metal “popper” and a strip of Kapton tape holding it all together. When the button is depressed it pushes down the popper which inverts (giving the click sound), while creating an electrical connnection between its corners and center.

The connection might be failing to trigger due to the flexible metal “popper” not properly connecting at the center and edges when the button is depressed. This could be because when the popper clicks and inverts it isn’t quite touching at the center.

The following might be worth attempting:

  • The popper is held on top of the pcb with Kapton tape. Peel off the popper and completely remove it from the pcb.
  • Put a tiny dab of solder paste in the center of the pcb where the popper touches when the switch is depressed.
  • Apply soldering iron to it. The goal is to add a tiny bumb directly where the popper hits. This should cause the switch to reach connection without having to depress quite as much. I would aim small. A dab the thickness of a piece of paper might be all that is needed.
  • stick the popper back in place, reassemble and test.
  • If the switch action is too soft or fails to click, it is quite possible the dab you just added is too tall. Remove the popper and file it down with a small handfile, or use a solder removal tool and reapply the solder.
  • I expect this may take multiple attempts of fine-tuning to get it just right. You might need fresh kapton tape to hold the popper in position if you try this too many times as the glue on the stock tape might wear out.

Some additional notes:

  • I recommend avoiding tampering with the popper unless you’ve given up all hope of anything else working. If you damage or destroy the popper, it might not be reparable. For these reasons I suggest against trying the following except as a last resort:
  • If the problem is connection between the corners of the popper and the pcb, one possible solution is to solder one corner in place while leaving the others floating. The downside is any heat applied to the popper might destroy its springiness and destroy the switch. A better option is probably to completely remove the popper and clean all corners with deoxit.
  • Another option that might improve springiness is to bend one or all of the corners slightly down. In theory this might mean more tension is required to actuate the switch. But again, the risk of permanently destroying the popper is high.