My Convoy S2+ just got really dim

I’ve put in fresh batteries and the light still can’t go back up to max brightness. It seems like each mode got cut by 2/3 brightness. Any ideas about what might have gone wrong in the light? I have an M2 in the same tint so it’s easy to notice the difference.

Measure current consumption at the tailcap. Also cell voltage.

Make sure things are tight inside. The brass retaining rings have small holes so you use an awl or strong pointy punch to tighten.
Ring in the head is normal thread direction for tightening.
Tail cap switch is reverse threading, so you want to loosen it in order to tighten it.
Make sure the contacts and threads are clean.

got pics of the inside of head and tail?

Just checking — you mean ONE fresh battery, right?

You can’t use two (CR123 or RCR123) cells in this light — they fit but the combined voltage is too high.

Yeah, only one battery at a time. fresh batteries meaning I tried more than one battery to see if it was the battery causing the problem. Tried tightening and cleaning. Still no go.

Here’s the driver and tailcap.
Tailcap measurements were zero since after tightening and cleaning, the light went out completely. Now it’s not even dim, it’s just dead. Not sure what’s happening. Could the soldering joints from the driver to the pill be affecting it? My old S2 and M2 don’t use solder points, instead they have a retaining ring.

Do you have, and know how to use, a multimeter?

First thing you can do is use a paper clip to bypass the switch:

Set the tailcap aside. It will not be used.

Put a charged battery in the flashlight.

Use a bare paper clip to connect the negative terminal of the battery to the body of the light. If the light lights the problem is in the tailcap. If not the tailcap is fine and the problem is in the driver or LED.


Yeah I have a S2+ just like that with soldered driver to pill. I bought it from FastTech. I was kinda upset to see it built that way. That is the only complete S2+ I have bought. For the price I looked at it as a host anyway, but the solder and no retaining ring ruined that idea.

Not sure if you mentioned, but where did you get yours? Mine is also the 7135*8 same looking driver and that Q-lite looking spring. \
I have never bought a complete S2+ directly from Simon so I can not say if this is the way he does it for the 7135*8 or if its some FT build with Chitty driver. I haven’t used mine enough.

Pic of my driver

Also I just replaced a New Bum tail switch in a different S2+ host. Have you tried a test with the tail off? use a screw driver or something across the body and touch the Neg on batt. Basically eliminating the tail SW.

Yep. Have one and yep, know how to use it. It’s not super accurate because the leads aren’t high gauge and aren’t hard wired into the DMM. But I’ve done tests before to get relative measurements so I know it works.

Edit: and the measurements are with the tail cap off.

You can take a battery or power supply (outputting 3 plus volts up to 4.2 volts) and see if it lights up when you connect the + lead to the driver spring and the - lead to the negative ring of the driver. If it doesn’t light up then touch part of the pill with the - lead. If it lights then the solder bridge is bad. If it still doesn’t light then I would remove the pill and see if the LED lights up when you touch the +/- mcpcb pads with the corresponding leads. If it lights then it’s a driver issue. If it doesn’t then I would replace the LED (but worse case is that both the driver and LED are bad).

He doesn’t need to do this since he already got zero’s with a tail cap reading where the switch is not in play.

There really isn’t anything bad about the 105D driver. It’s just a newer version of the 105C. The tail cap threads are anodized so contact has to be from the end of the tube where it’s bare aluminum directly to bare metal in the tail cap. When you use a paper clip be sure you touch it to bare metal not black ano which does not conduct current. You might need a metal shim between the switch pcb and the retainer ring. Or the driver is bad. We’d need pics of the driver’s other side to see any visible defects.

And don’t be staring at the LED when you make the connection …

I was going to mention that but I forgot too. I’ve done that before (once) and it’s certainly something you don’t want to do if it fully lights up :sunglasses:

so after some disassembly and more cleaning, i got the light to turn back on, but it’s still super dim. The measurements on my DMM are 0.02 on high and 0.01 on mid. When I test my M2, I get 2.7A on high. So my DMM is working correctly. I would have to desolder the driver from the pill to take a look on the other side. I don’t have time to do it now, but I’ll try later tonight.

Likely a bad driver then. Your springs don’t look discolored which happens with a short. Output us about what the mcu alone delivers through pwm so the 7135’s are either fried or not properly connected.