Convoy s2+ wonky from new, need some advice

I just got a red Convoy S2+ from aliexpress, it’s great except if you even breathe on it it goes all flickery, seller ‘helpfully’ tells me that it’s probably a loose connection somewhere…

Anyway so I can see on the inside of the tail cap two little holes which presumably you stick some sort of tool into and turn (I know the tail switch is reverse threaded) what the heck tool fits in those holes, they’re like 1mm around.

If anyone knows what tool fits, I’d appreciate a link (I’m UK based, so UK if possible)

The other end though, I’m not seeing any holes there, so if it’s the head end that’s loosely connected, how would I go about tightening it?

It looks to be a nice torch, just marred by not being able to use it properly.

Search for “camera lens spanner wrench” and you should find lots of choices for a tool that will work for you. Im not sure where you are, but Amazon has lots to choose from, and so does Aliexpress.

I use a pair of scissors from a Swiss Army Knife. The tips fit well enough in the holes to turn both the tail switch and the pill.

It may be the anodization. Convoys have electrical issues related to the anodization not being machined away properly. (anodize is non conductive)

To answer your question, the tool you would want is called “snap ring pliers.” They come in “internal” and “external” configurations, and there are also “convertible” kinds that can do both.

Yeah, I’ve had good luck with snap ring pliers for those retaining rings (with the tips somewhat sanded to be thinner), but if you grab a pair of needle nose pliers and file the tips into long points, they can also work and can be found more cheaply/commonly.

Otherwise, you can also check the ends of the body tube, and see whether they’re covered in anodization (which you can sand away until the ends are shiny) or grease (which you can wipe away and clean with rubbing alcohol). While you’re at it, check the head/tailcap springs for any oxidization that may need cleaning away too, since those compounds are typically less conductive.

If none of this helps, you could also see if the problem goes away if you remove the tailcap and bridge the connection between the battery and the body tube with something conductive - if the light works reliably in that setup, then it’s probably an issue with the spring/tail switch. If that’s the case, you could unscrew the tailcap retaining ring, and inspect the soldering around the switch/spring for a possible bad connection. If everything looks good, the spring doesn’t look super compressed, and you’re sure it’s the switch, you can grab a replacement from FastTech/AliExpress for at most a couple bucks.

EDIT: Hold on, there are no holes at the head end? You’re…sure there isn’t some sort of metal ring you can unscrew there? That’d be a bit weird and concerning - if you’ve got a photo that’d be helpful.

A sturdy geometry compass or a divider can also work as will needle nose pliers but the camera lens tool seems like a top choice.

Ok to address some of the comments.

The torch is brand new so no corrosion

springs don’t seem to be compressed or corroded, you can feel pressure when screwing the ends and there’s marks on the battery indicating the contact is firm.

Not feeling excess grease either.

Anodising, the tail end thread looks to be anodised, the lens end is not.

I made a couple of youtube videos showing the flickering.

Convoy S2+ flickering

Convoy S2+ more flickering

Here’s the pictures.

Switch End

Main Body

Lens End

My first S2+ had that issue.

Tightened the ring in the head with some needle-nose pliers, no more flickering.

Yours looks different than mine though, no solder blobs and different color driver.

Look at the ends of the springs where they were cut off. Is the metal coming to a sharp wedge point that has a small contact area with the battery?
A little motion can make that kind of contact bounce or carve a groove into the battery.

If so bend/file the end of the spring slightly to maximize the contact area, then add some conductive lubricant (“bulb grease”) (Nyogel) at all the contact points and on the threads after cleaning them up.

Needlenose pliers, or pointy tweezers, or 2 small nails poked through holes in a piece of wood, will give you the leverage to tighten up the driver and tailswitch. Maybe loosen and remove them first to clean out and lube the threads.

This is now the third time in just a few days that I must correct that mistake: “Bulb grease” and Nyogel (760) are not conductive! They are an electric insulator. But they are used to protect electric contacts from corrosion.

Oh, conductor?

Nye sells several different greases, and I have small containers of both kinds thanks to someone in the deep past who parted out a quantity of them.

https://www.nyelubricants.com/electrically-conductive

The people you corrected may have either variety.
They can look this stuff up[ to check if they don’t know. It’s possible they in fact do know what they have.

Nye warns about gooping up a space that needs sometimes to be empty like a sliding switch.

:https://www.nyelubricants.com/stuff/contentmgr/files/0/ed06f9d2c6181654474e826bfc616a9a/en/758g_overview.pdf

Searching around for the exact product number will find, e.g.:

I specifically meant people who claimed that “bulb grease” is conductive. But using something conductive as bulb grease would only cause a short circuit. Same with conductive Nyogel, which is not intended to be used in flashlights where it can easily travel the short distance onto the PCB and cause a short circuit. I think the common use for a conductive lubricant is when you want to improve the ground path in moving parts. In another thread I also explained recently why a conductive lubricant wouldn’t improve the connection in a flashlight.

But for us flashlight enthusiasts it should be enough to know that it’s probably a bad idea to have anything conductive in a flashlight that can move around.

Blah blah blah… Any time I have any problem that seems intermittent, whether the light flickers, goes mental, whatever, first thing I do is undo then redo the retaining rings on the driver and the tailswitch. Takes care of like 95% of those problems.

Failing that, disassemble then reassemble the tailswitch first, then around the driver (some are almost press-fit to make the ground connection, and weird, despite the ring). Especially the tailswitch, disassembling, reseating, then tightening back up, typically takes care of another 4%.

The last 1%, well, who knows.

OK I’ve ordered this from amazon, should come on friday.

Camera Lens Tool

loose rings are the only issue i have had to fix on these over 200+ units.
and that amounted to 3 units.tighten and carry on….

200 units?? you have 200 flashlights?

Don’t you? :frowning:

EDIT: just kidding.
IMHO the two NAILS method always work.
If you want to be able to apply more pressure, you can replace one (or both) nails by an awl.

OK just to make sure, once my tool gets here, it’s reverse threaded on the tail switch ring right? and normal on the led end?

I agree with Lightbringer. I'd actually disassemble it, reseat parts and put it back together. Since your driver is soldered in, I would think that isn't the issue. I don't think needle nose pliers were mentioned but I have a few with small tips that even do the job.

It's no fun having this issue. Just today, my S2+ was somewhat intermittent and then completely stopped lighting up. Turned out it was a loose retaining ring on the spring side of the driver. However, barring two bad solders at the head, I think you have a loose connection at the switch. You may confirm this by removing the tail cap, place the head pointing into a transparent, firm material, leave battery in and bridge/connect tube battery tube to negative end of battery with a paperclip, bare wire, etc. . If the light performs normally, the problem is in the tail. I think you have the Biscotti firmware so it should be in mode one.

Splitring Pliers.
STRAIGHT arm.

The ben t ones can run out of reach before getting there.

Nail Scissors at a pinch. But expect them to slip regularly
Tapered tips.