Help getting through my first build.

Is there a common culprit to beginner fails? Here’s what I’ve done…

Convoy c8 host (MTN electronics)

A6 driver (MTN electronics)

xpl high emiter (mtn electronics)

*driver came with wires and pre bypassed from MTN electronics.

I pulled the wires through the holes, and stuck the led to the base using thermal compound. soldered red wire to the positive, black to the negetive emiter pads. then bypassed the tail switch spring as per YouTube. I’m no pro but everything looked ok.

flashlight did not turn on.
tail switch bypass was not the problem. I know that because I put it in my S2+ to test it and it worked fine.

I can’t figure it out. any advice?
is black supposed to be positive in flashlight land or something?

Forgive me asking the obvious stuff.

The battery is charged?
The battery tube is in the right direction (non-anodized threads towards the head)?
Everything is snugged up?
Driver is well seated and centered? Retaining ring threaded all the way down?

That’s what I’d check first (easy stuff).


Charged battery, everything was snugged up. I couldn’t tell you at this point how tightly the retaining ring was held on since I desoldered the wires and now my soldering tip wont get hot to resolder it to test that. Realy frustrating.

What roll does the driver retaining ring play other then keeping the driver in there? Could it just not have been torqued down hard enough?

The retaining ring keeps the driver in place yes.

The driver needs to be properly seated so that it has a connection to ground. That is why I also asked if it is centered. If it were skewed to one side of the recess potentially it might not be making good contact. OR. Being skewed to one side of the recessed pocket could be grounding something that is positive, like the + to the led.

Also. I know you said you confirmed the switch worked in your S2.

But you could also remove the tail and switch completely and use a piece of wire (or anything metal, a paper clip) and connect the battery negative to the battery tube end. Maybe the switch worked in the S2 but not in the C8. Helps to eliminate all potential errors even if unlikely.

Be patient, there are many C8 modders here. I am pretty sure the retaining ring makes contact with the driver and is part of the electrical connection to the body. So a bad connection there would be a problem, it should be tightly clamped.

Might I add, do a simple continuity check between the + of the LED and the body of the light. There should be no direct path between those two points. Is there also a chance you can remove the wires from the MCPCB and direct drive it off of a battery to make sure the the emitter is not defective.

Hats off to your for rolling your own lights. My eyes can’t do it anymore so I admire those who still can.

if you have a tester/meter it’s always best to check for shorts before you fire a light up—I fried more than one driver learning this lesson

Got it resoldered, torqued down the driver retaining ring and now it works! Problem is it only has one mode now. Any Idea what might be causing that?

is it high mode—-reflector shorting ground

Well the problem can only be in the driver then.
Something must be/have been shorted. I’m not familiar with that particular driver. How close are the components to the outer perimeter? Close enough that they touched the flashlight body?

(The switch is a standard non-illuminated switch, correct? Sometimes illuminated switches can cause problems switching modes)

Edit. The problem is likely with the driver

Thank you all for the generous input.

So this was basicly my first solder ever. Super sloppy at best. I think perhaps a piece of solder may have been touching something it shouldn’t have.

When trying to figure it out, I noticed a small flake of solder coming off the joint where the negetive connects to the driver. It was protruding outward and very possibly touching the tube. I don’t know if that’s what was messing things up, but when I tried fixing it, it broke the connection. I’m going to have to start fresh with a new driver. Yes I’m sure any of you experienced guys would just fix it but Id rather just get a new one and start fresh.

Before this project I watched a bunch of soldering videos on YouTube. All I can say is that soldering is way harder then it looks. A real skill and craft.

Tips won’t tin, solder won’t stick, burnt fingers, lots of foul language etc.

I’m going to give it a little practice this time before taking to the actual light.

Also this wasn’t an eluminating switch at least as far as I can tell.

Last thing.
Is it voodoo or something? Bran new iron. Wrapped it with solder as per the internet,let it heat up and melt the solder, with in 20 min, my tip was charcoal and totally not functional. Drove me nuts! Ok ok, more YouTube’s I guess haha!

Thank you all.

Clean the tip, over and over and over and over, while you are using it or if it even sits too long in the holder. You can use that brass tip cleaner, it works very well, along with a damp sponge it will keep your tip shiny and working well. If you are having problems tinning wires or solder not sticking you probably don’t have enough heat. I don’t know what kind of iron you have but spend the few extra dollars and get one with a adjustable heat setting and buy decent solder. I don’t use lead free solder but that is entirely up to you. I don’t think lead free solder flows very well at all and makes for ugly joints.

Grab ya a breadboard and rob a old TV or something for some parts and practice. With a breadboard and a TV you can actually build your own radio. Look up the plans online.

Like I said, my eyes are shot for that little stuff. Build while you can.

Will do. I got the lower end Weller with variable temp ($40) .Solder was some led free stuff I got from home Depot as well as some leded stuff from MTN electronics. I was messing with both. Is there a solder that you can recommend? Also, I’m going to need a new tip now. What style is best for this work?

That is the type of tip I use for most things. I use a 60/40 Rosin core solder, the thinner gauge the better I find works well, less surface are to heat up. Sounds like you have a good iron. Just get the tip in good shape and have good solder and you should be good to go.

I am by no means a expert, I just learned from experience and making mistakes. I’m 46 and still learning, just ask my wife. LOL

Perfect! I’ll go buy a few of those. Thank you!

This is a great Iron that can generate enough heat—-Heat is the key and good Tips—I’m not sure of the 2 sizes I use —one kind of small with a point—the other larger with a flat area like a screwdriver ( for max heat) make sure you get authentic Hakko tips—I’m not positive those amazon linked ones are—I finally bought a second station—one for each tip—-RMM told me he used these stations and tips for well over his first year in bussiness