Fenix TK61 teardown and mod thread

I also think that it should be within that territory…. I think the poor finish of this reflector is the cause, you did something? try to clean it? does not look like std TK61 reflectors

No, I didn’t do anything to it, other than cut the bottom out.

Ordinarily if an aluminum reflector has ripples or lines in it I’ll hand polish it out. I’ve had great success with this. Again though, can’t do that with a plastic reflector. Beats me. I’m planning to search for a good reflector that will fit in here and see if I can get a better result.

Anybody know where a TK61 reflector can be found? Or one from another light that will fit this one?

Hi guys, did anyone measure,

Stock TK61, dedome only, current bump + dedome, how much cd does it increase with current, is it linear or at least close to it? based on this, it should be 1700 lumens or lets say 1650, does this means around 60% throw increase? thanks.

Vihn has some serious update with v2.0
I would like to see the driver he used. TK61vn V2 - Throw King +740K Lux ;-) | Candle Power Flashlight Forum)

Ill put my money on the HX-1175B from RMM (Not official yet).

It that is the case, its the driver I mentioned early in this thread a few months ago. ;)

(but with some tweaks that have cost RMM a ton of emitters to figure out)

Shut up and take my money.

a question:

why do you try to replace a p-channel transistor c01c by an n-channel transistor (70N02) ?
i mean it can not function as.

Different polarities, one triggers with pulling the gate (or base) to ground, the other applying a voltage

alot of reading…but hope that helps

Welcome to the forum phil76.

It was just a quick test I did for RMM.

Latest and greatest driver "mod" for the TK61 might end up being this.

Just an FYI- I’ve already corrected the issue tterev3 pointed out in the .sch, just need to fix the board (I added a gate resistor, series / limit resistor (or whatever the name for that would be) and BJT to facilitate the P-FET shutting down all the way.
This is high on my priority list but not at the top and I till I can secure a TK61 for testing I seem to be lacking motivation with all the other crap I have to do (hey I just posted the project 3 days ago, cut me some slack lol).

My TK61 arrived today. Batteries took a couple of hours to come up to 4.2.
For my short available range it lights up well. This weekend I’ll give it some distance over water.


Voltage regulator fried, I think it is that same type like the regulator near, type “C01C”. Can anyone help checking his tk61’s driver?
Before I removed it only lowest mode was working, after removing flashlight is dead (pretty normal?).
I found some components in aliexpress and I plan to buy some. If I bridge the spot over there, what will be the results? Do you have any idea if I can find one of these regulators in other drivers?

Does this RaceR86 pic answer your question? Appears to be some type of FET you are pointing at.

Yes and thank you.
I destroyed Q4.

I’m sorry for what happened, I see also the encapsulated coil it’s broken :~

It was broken before the regulator’s fail and I had no problem.

Hi there guys!

I just bought some Fenix TK61 that I want to control from a arduino chip. Has anyone here tried to do that? I want to be able to start a special light sequence that the arduino will trigged in a stage performance I’m creating. In the best of worlds I would love to be able to dim the light form 100-0% be able to strobe it and have total control over the light. Is it possible to just let the arduino control the power button, and do fades of the light beam through pulses in 100% brightness mode? And where on the torch’s circuit board would you guys solder the chip on (pre or post the power button, or somewhere else)? Hope that the purpose of the project is clear enough for you so you can imagine what’s needed to be done. Looking forward for some answers form the Pro’s : )

All the best from Sweden.

It’s not that easy as it may look. You can control power button on the flashlight if the button is an electronic “switch” but if that button is only used for power on and off or mode 1 mode 2 and mode 3 that’s all you will be able to get using arduino, ona and off…
To have absolutely full control over the flashlight you have to find PWM pin of the MCU used in the flashlight, lift it from the board or unsolder it and use arduino PWM pin to control the LED, of course, for that you will have to write the code that you will run on arduino board.

Yes, that was the plan. To either replace the on/off switch with a relay or pwm the led driver.
So I guess the question is:

- can anyone identify the pwm pin on the TK61 MCU?

  • would that interfere with some over/undercurrent or other protection logic inside the original MCU?

I’m still amazed to how this light can get 171kcd with domed XML2. The magic is in (plastic) reflector. While it’s not the most pleasant choice for most of us, shaping plastic is much easier than metal. I will prefer this plastic reflector rather than ugly knurled aluminum one - performance wise.
Fenix has discontinued this TK61, and will soon replace it with more mainstream thrower emitter like XHP35HI. My guess, 300kcd stock is easy even with current TK61 reflector. Any clue as to the launching date?

- Clemence