Boy am I pissed at Sunway...

I have an M40C that I was modding. A nice neutral XM-L was going in, MC-E coming out. You all know I'm extremely careful with my work. That's all it was-a straight star swap, and that was it. Only had to take off the bezel, two screws holding reflector in, and star was immediately accessible.

I go to power it on, and it just flickers. Next thing I smell is the magic smoke. I quit in disgust, now it's a $165.00 host.

No wonder I don't buy production lights any more... like cars, complicated electronics don't belong in flashlights!


What has this got to do with Sunwayman? It worked fine before you modified it didn’t it?
I feel your pain however as Bill Clinton used to say :slight_smile:

Many MC-E lights are wired in series for a total of around 12v input.. Trying to just put a 3.3v vf XM-L in there was asking for that to happen really. The good news is that this should mean the driver is still ok and you can replace with another MC-E or possibly consider an XM-L EZ-white as they are 4 die too.

And that, my friends, is why I put my soldering iron in a drawer and haven't taken it out since last summer.

Nope... driver itself smoked. Been at this for a long time. XM-L went into my TK-35 and works fine.

Are you sure? The XM-L could have been fine too as the input would have been way too high and it may have just not taken much/any current. Have you tried replacing the original MC-E as it was originally wired?

they are not meant to be modded...

Especially around this bunch .

Dorpmuller , Richpalm , I am a longtime fan of your mods .

I know you'll figure out a way to make that light nice and bright in no time at all .

Ouch. Sorry to hear man. Anyone want to elaborate further on the mce led lights being wired different? Seems like most lights take emitter swaps just fine.

It's always the expensive ones that make smoke my Nitecore EZAA puffed a big hit out after a neutral emitter swap and it actually vented a Duraloop which I didn't think was possible.

Not all is lost. You still have a quality host that should be moddable. I know that doesn't do much to soothe the frustration. We've all been there. I actually opened up my V60C - got the bezel, lens, and reflector out. I just looked down marvelling at that XML and thought..."I better just leave this one alone".

I cannot comment on the M40C specifically, as I am not familiar with it.

However, just referring to MC-E LEDs in general, the MC-E as you no doubt know has four chips. What you might not know is that all four chips can be adressed individually.

They often come mounted on stars that arrange the chips in parallel, and you then just have to solder two wires to the star, and supply the right voltage and current to those two wires. The traces in the star will do the rest. Likewise, you may have a star that connects all the chips in series, and again, you would just need to solder two wires, and supply the right voltage and current.

If you had a bare LED, you could yourself wire the chips in series, or in parallel. However, the four chips could also be wired so that they were arranged two series/two parallel.

Wiring the chips in series would require 14.4V (assuming 3.7V forward voltage per chip) and 0.7A current. In parallel, you would be looking at 3.7V and 2.8A. Two series/two parallel would require 7.4V and 1.4A. Basically, you can think of the MC-E as being four entirely separate LEDs, each running at 3.7V and 0.7A. You then have different ways in which you can arrange those four LEDs.

So, if the M40C (or any other MC-E equipped light for that matter) were running the four chips in parallel, you could switch the LED easily enough. 3.7V is more voltage than an XM-L really wants, but not a million miles away. On the other hand, if the chips were arranged 2s2p, or in series, then the XM-L would be receiving more than two times, or four times, the voltage it should.

MC-E has four dies. Four individually adressable dies, meaning it can be wired serial, parallel or a combination like 2s/2p. It was designed to be very flexible for many applications. According to the M40C specs. The light will operate from 5.6v to 12.5v so that means possibly it is a 2s/2p or the board is a boost?

Anyhow that's all I know, which is next to nothing.

I'm sure you will figure it out Rich

That's hardcore. Thanks a lot Stephen Wallace, and old-lumens....

I have tried to open my TK, with heat, lathe chuck, spanner to no avail.

How did you open yours?



Oh, absolutely! I got the driver out and saw burned up things.

Like others said here, I'm gonna do something with the host.

There is no booster coil on the driver. No wonder I stick with 7135's!


Head clamped in a big bench vise with a propane torch, full throttle, applied right to the head, and twisting the pill with all your strength. Not recommended-there's every chance of destroying the head.

I hate threadlock with a religious passion!! And Fenix's is concrete hard in copious quantities.


Thanks for the directions.

I now know I didn't try hard enough