TK75 teardown, resistor mod and R86 edition

Flashlight Modding and DIY Parts
1

Tearing down the TK75 is basically like the TK61.

That means, that the bezel can be unscrewed quite easily with strap wrenches. The green contact board can pried out out with a small screwdriver or two. My TK75 is an XM-L2 version. Not sure if that makes a difference to how easy it is to open and such. I wonder if my driver is 4th generation driver (V4) since its labeled like that. Date says 2012.11.26.

Ill try to share a fair amount of pictures in this thread, but I did not take pictures of everything. Its a fairly long time since I did the teardown and resistor mod, so I may be off on a few details.

TEARDOWN

Unlike the TK61, the resistor to play with are on the backside. So you need to get in from the front of the light as well in order to get the driver wires off the mcpcb.

Unihead:

Nicely sized direct thermal path copper mcpcb attached with screws. The plastic reflector centers to the edges of it, so I would recommend sticking with the stock XM-L2`s and that mcpcb.

Like in the TK61, there are two plastic pieces below the driver. Drag one out in order to get the other one out. Its a tight squeeze.

Red wires goes to the power switch. Black wires to mod button.

All the plastic parts.

Battery carrier "naked" without the plastic case. Two diodes for battery reverse safety I believe.

Resistor mod

Ill just share my personal notes. I played around with some resistors and numbers. Dont expect presision on the % numbers and such. Some of them are taken from a power supply with analog readout.

Short story. Stock emitter amps were about 2,9A (2,88A in the table above). Turbo is regulated down to 6,5V input.

I believe I had read a post about someone using an R030 so I threw one on top the stock resistors without doing any calculations. Turbo increased with 26%. The lower modes increased with 82%. That is not good, so I swapped the R30 for an R100. Still a 26% increase on Turbo. Slightly higher on the lower modes. My notes say 3,65A to the emitter, but depending on flashlight temperature and how long it was on, I could be looking at numbers as low as 3,35A or 3,5A. 3,65A is just what I consider peak. Another thing I noted was that input amps seemed to have increased slghtly more on Turbo compared to the other modes.

Therefore I tried an R120 instead. 3,5A on high.

Conclusion resistor mod

On my driver (marked TK75-V4), I would say that if you are only doing a resistor mod, R100 or R120 on top of the stock resistors is the way to go. It will increase output on Turbo with about 21-27%, and not mess up the mod spacing. But, I was not that happy with such a low increase.

1. On the stock light, output on Turbo is properly regulated. After resistor mod, it was not based on what I remember from my driver. Basically, it then looked like it was dependent on high discharge cells in order to stay in regulation. Meaning, that with regular cells run used for some time, there would be no increase over stock.

2. The mod did not increase output that much, and with possible reliability issues due to more heat, not so sure if its worth it. Especially considered that the increased output did not seem to be well regulated.

3. Playing with transistors or who knows what may make that exact driver do more, or just having a different TK75 driver might give higher output. I know others have resistor modded their drivers beyond 4A. Actually, my attempt is the lowest increase I have heard of... But, I also know that two lights that have been modded harder have failed due to heat issues when used too long on highest setting without adequate cooling.

4. Im no fan of possible reliability issues or output increases that are only for a limited time.

5. Need more powah!! Check out next post for more details for my idea of the ultimate TK75. It seems names are imporant. So ill just call it the TK75 R86 edition.

2

TK75 R86 edition

This mod is based on the Taskled H6Flex driver. More technical info. Oh, yeah it comes with a tiny user manual as well. 32 PAGES! It costs 40$ + shipping. (10$ if you are outside the states.) I want to thank MRsDNF for putting this driver in his scratch build light. Not sure if I would have thought of it otherwise.

Lets just cut to the chase right away with some numbers measured by me. Slightly higher compared to Fenix due to my current calibration. These numbers are comparable with each other, and I believe they are quite close to jmpauls320 measurements on vinh lights.

TK75 stock. 3150 lumen, 129kcd (2,9A to each emitter)

TK75 resistor mod: xxxx lumen, 154kcd (Up towards 3,65A to each emitter)

TK75 R86 edition: 5112 lumen, 207kcd (6,6A to each emitter of the stock emitters. Properly regulated. 5334 lumen on startup)

WOOT! Did you notice the red battery light in the middle of the buttons?


Some R86 edition specs:

-6,6A to each emitter, properly regulated! (Ok, with 3,4V resting voltage its a bit out of regulation but still close to 5000 lumen. At 3V, its still brighter than a stock TK75, and most will probably not run the batteries below 3,4V. With quite low voltage batteries, expect around twice the brightness vs a non regulated hot rod (Shocker, etc, etc)

-3 stage fully configurable battery monitoring system

- Medium voltage, red LED lights up

- Low voltage, red led blinks (can be configured to lower power to desired mode as well)

- Cut off, double blinks for a minute, then shuts off. Light can be turned on again in case of emergency (How this works can be configured too)

-User configurable temperature monitoring system

-Can be set to 50 degree celcious, 60,70,80,90 or off. Im using 90.

-User interface fairly similar to stock, but more modes and no blinky stuff.

- Right button for on/off. It is now a mechanical power switch (absolutely zero power drain, and much lower risk of accidental turn on)

- Left button for mode changes (Im using UIP UI, 7 modes and startup on lowest mode. Quick accesses to high from off. Can adjust brightness back and forth. Quite similar to a ramping UI, but with well spaced modes.

- A ton settings that the user can customize, various UI, etc etc etc...

How to do this mod:

Im not doing a step by step on how to do this mod as there as lots of steps.

But ill share several pictures of what I did. I dont have pictures of everything. I would not consider this a beginner mod. Mod is involving and its being done on a expensive light with an expensive driver. Know what you are doing and don't mess up are my best tips. And figure out things yourself, instead of sending me a PM. 0:) ... Or just ask in this thread.


These are the modifications I did to

Body:

- Copper insert in pill

- JBwelded the hole in the middle of the light to become flat for good heat transfer to the driver

- Drilled new holes through pill for emitter wires

- Drilled hole for battery light

Carrier:

-Rebuilt from 2s2p to 4s (I removed the diodes since I did not know their specs)

-Added extra wires to the springs

Plastics:

- Trimmed backside of both the large plastic pieces a lot to fit driver at the bottom of the pill. Lots of trimming required.

- Cut stock switch board in half. Replace one momentary power switch with a mechanical Omten switch. Lots of trimming on the plastics to get the Omten switch in place.

- Trimmed the little plastic piece above the Omten switch to the correct height

- Trimmed a hole for the battery warning LED

Driver:

- Programmed to suit the light and my preference (this is quite time consuming, remember that 32 page manual)

- Added suitable resistor for the battery LED and input voltage

- Attached driver to pill with fujick (Thermal pad that came with it was recommended, but needed to move it around a bit after putting it in there, and found it easier to use fujick since I have never used one of those pads)


Emitters/MCPCB

-Lapped mcpcb

-Currently using stock emitters (This light might end up in the hands of a local. If so, ill build a new light for me, with some NW emitters and maybe a subtle tint mix. I would try and stick to as close temperature as possible and perfect tint based on how emitters looked if I were doing any mixing.)

Misc:

- Lots of messing around to get everything nicely in place.

- Testing driver before putting it in the light, and also in the process to see that everything worked nicely.

- Shrink wrap around wires (from driver board to switches and battery LED)

- New high quality thermal paste under mcpcb

- Made hole in switch cover for the red battery warning led

- "Burn in" heating it up in order to avoid condensation on lens (I have not done this yet)

- Clear silicone on battery warning LED in order to make it even more water proof (not done this yet)

- Glue battery monitoring light in the correct place

- Glue switches in place

- Glue /fujick mechanical switch connections so that vibrations cant damange it.

- Glue /fujick under the (stock driver) aluminium retaining ring so that it holds all the plastics nicely in place (not really necessary).

There might have been more details, but the above probably covers most.

Some pictures:

Not sure if I will put the plastic cover on top of the carrier back in place. That would need trimming since I put the wire on the top side. I could have made it more subtle, or 100% stock looking from the top, but I want it to be different compared to stock carrier. I already did the mistake of putting this in my TK61 (did not use the light or damage it). Having this 4S carrier similar looking to a stock 2s2p carrier is not recommended when having several lights that uses these.

I ended up with some excessive heat shrink wrap around the wires since I heated several when they were not in the right place. :X

I considered to make plate that would sit where the stock driver used to be, but the aluminium retaining ring presses on two of the small plastic bits, and I used some glue/fujick elsewhere to make sure everything is nicely in place.

Might put in some beamshots, comparison pictures with other lights, etc..

,,,,,,

Last words

Are there any cons? The mod, and setting up the light is a quite time consuming process if you want it to work perfectly with heat monitoring, battery LED, mechanical power switch and adjust it to your preferences. If those things are not a priority, it can be mounted in the light in a much easier and quicker way. For me, having those features is important and enhances the user experience a lot.

Im currently using UIP (read the manual) + startup at lowest mode. I would have liked to perfect the UI a bit. But to make it short, its a nice UI. The only thing I can think of being an issue to some is low PWM on the lower modes. UIP have 7 modes and the 3 lowest modes have visible PWM if its raining. I can also hear a faint PWM sound in those modes if its 100% silent and I listen for it. For normal outdoor use, I would say its silent. There is no moonlight, or super low mode. Mode spacing is good though.

Stock TK75 is a great powerful allrounder, now, this light is in a different league. Im not kidding when I say that my BTU, SP03, Lustefire 3xU2, all modified "hot-rods" are now pretty much obsolete. As in, this TK75 outperforms them in pretty much every possible way. This will probably make some of my incoming Supbeams X40 and K40M obsolete as well (hopefully Ill like the thinner carrier enough to keep them). This might make some other lights that I have been planning mod obsolete as well. This will also out throw X60. Naturally, It wont run as cool as a much larger light. But it will fit in my jacket pocket, and that makes it into a light that I will use much more compared to something that is larger.

Used in a mild/cold winter environment with some wind or maybe rain. It might be able to run at 6,6A without step down from full to low batteries. Now, late summer/early autumn with some wind I can use it for around 6-8 minutes before it steps down. Wait until it cools 5 degree (which is fairly quick) and I can crank it up again for a little while if needed. I can disable the feature, but I prefer to have it there for safety.

If you think 6,6A is over the top, or generates too much heat. Then its easy to adjust it down to 6A, or 5,6A or... 5A .... Well, easy once you are confident in how to operate the driver and how the menu system works.

I can go on and on, but the main thing is. The light is now frickin awesome!

...grumpy cat approves...

3

Very nice mod! You weren't kidding when you said it was different from the standard Vinh mod.

I'm very curious to see what numbers you will get when you get your X60 though.

4

What an amazing mod RaceR86. Lots of wires in one of the pictures scared me.

5

+1 to what grumpy cat said :-)

Great mod! Sounds like a really versatile light now. Wish there were less expensive buck drivers like that but the taskled drivers are surely in a class of their own though.

Thank you for sharing !

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4S input now, but still with the LEDs in series?

7

[quote=InfinitusEquitas]

Very nice mod! You weren't kidding when you said it was different from the standard Vinh mod.

I'm very curious to see what numbers you will get when you get your X60 though.

[/quote]

Thanks! Yeah, im not sure of anything around this size that puts out the throw/ lumens combined with sophistication and built quality in a nice to use package.

Why do I still need X60? Please talk me out/into it. :D I like lots of flood for walking around, but if I need a ton of flood in a 6x18650 sized light. I can just use my retarded 12 XM-L light if I want big output (still need some changes to it.) That will outperform a modded X60M.

I got a Solarstorm/Fandyfire L3 (6x18650) light, and Im planning on making it into a 3x18650 light. I feel its just too long.

Compared to my TK75 Im quite sure that X60 will be very similar or marginally brighter before stepdown. Less throw, especially after step down. Id rather have 4 batteries in the light, and 4 spare batteries on my body (jacket/backpack), then to walk around with a light that is much larger and heavier.

Thanks. How you been able to set up the taskled H6flex to your liking? What setup are you using?

I gotta say, having a power switch and a battery LED made it much easier (less difficult) to understand the driver when not being used to it and setting it up. There are still features I have not tested, and maybe some more fine tuning to the battery voltage warnings.

+1 to what you and the cat said. :D

The taskled driver is one of those drivers that I feel seemed quite expensive, but once Ive learned its features better. It offers so much more compared to pretty much everything that is supposed to rival it. Does anyone know if there are any other "high-end" driver options like that out there? Just curious if I have missed out on something.

I would have preferred to see some changes to the default UIP UI. But the hardware, performance and the ability to customize so much is nice.

Its my first light with a taskled driver, and Im pleased with what I got. :)

Yupp!

8

Hi, nice mode and well explained. I was following your thread about the Tk61 mod and that what I did to my tk61. I am new to flashlight modding but all I can say is Thank you for showing us all your mod discoveries. Going to try to order this Taskled driver for my second attempt to mod my tk61….need more power! :open_mouth:

9

TK61 needs no carrier mod, since input voltage is greater (2s2p) than led voltage?

10

Wow! I love that light!
I still haven’t found the nerve to start opening up and playing around with any high end, name brand lights. I bow to the awesomeness of that light.
Maybe I’ll start small with my TA21.

11

H6Flex has a minimum input voltage of 7v, 2SxP is not enough. It's more efficient with higher Vin. Input current with 2S would be double what it would be with 4S, and it would be out of spec if you ran the cells down to 3.5v each (input current would be too high to be safe, if it would operate down that low at all), check the H6Flex tech info page.

http://www.taskled.com/techh6flex.shtml

12

Cheers mate, and thanks for leaving a comment. Im not sure if I would bother using a using H6Flex in a TK61. Lots of work and investment just to drive a single emitter just a little bit harder, so little that its barely visible to the eye, and still not close to the XM-L2s peak potential. If you want more power then the stock driver can handle, RMM might be out with a HX1175B solution. I might start playing with my HX1175B`s and some tricks and see what I can do. HX1175B was my backup plan from the beginning, ive just put it on hold since others started playing with that idea and I had other interesting mods to do.

My plans with a mechanical switch on such done to the TK75, was first thought of for my TK61 mod actually.

If you want to use a taskled driver, H6CC might be an option too. Im considering to ask taskled if they will be capable of just a tad higher output a resistor mod or something. 0:) If it can do higher amps reliable without any strange behavior then it might be worth it for the most power hungry people.

With many buck drivers yes. But the relevant taskled drivers are made for higher input voltage, 7-25V, 8-25V and such. So I doubt they they are suitable for only two cells (5-8,4V.)

When all that is said. Lets try and keep TK61 talk to the TK61 thread and TK75 thread here in order to avoid confusion. Thanks!

[quote=Ouchyfoot] Wow! I love that light! I still haven't found the nerve to start opening up and playing around with any high end, name brand lights. I bow to the awesomeness of that light. Maybe I'll start small with my TA21. [/quote]

Thanks. If you are going to start, start with the lights where you have good backup solutions and are simple. That usually means, try and avoid lights with magnetic rings, and fancy electronics in battery carriers and such. It just makes life easier to avoid such things.. :D

13

you've been busy! Nice mod, thanks for showing all the details and the good pictures of them (not that I am going to do a mod like this: the light is too big for me, the work is too much for me )

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Yupp. Kinda. I have taken my time with it though. The taskled rebuild have been an ongoing project for many weeks. I usually suck at "large projects". So I take breaks, do other mods in between and such. Go a bit back and forth. Im sure this mod sat for 7-14 days at some point without being touched.

15

Thanks again from the info, my fenix tk61 dedome was my first thrower light and I was amazed on how it lights up the sky… a light saber! I am also thinking about your post on tk61 about the HX1175B driver if there is a potential to make it 7+ amps, my next option will be to try and order the maxtoch 2x and put the driver on the tk61, because i remember from your old thread that you did the maxtoch 2x @7.2amps. I am not worried about the e-switch of the Tk61 because i can put a DIY mechanical switch a reverse clicky. If it doesnt work then its fine at least then i can put it back the old tk61 driver :wink: . still a lot to learn from you, Thanks for sharing all your hardwork mate….cheers

16

It was probably Tom E, DBCstm or someone who did that maxtoch mod.

Once you go for a mechanical switch in a TK61 or TK75, it might require some work to go back. A fair amount of plastic had to be trimmed off in order to get the mechanical switch nicely in place. Espesially if you want to use a "large" Omten switch like I did. The mechanical switch in my TK75 feels one 100% natural though. In terms of feel, there is no way to tell that the light was not shipped from the factory with one.

17

Super heavy mod :open_mouth:
Thanks for the pictures and for sharing :wink:

Some questions If I can…207 kcd It is with dome on or dedomed?
The switch cuts off power from the batteries?

Many thank

18

Domed.

Yes. The mechanical switch to the right cuts power from the batteries. When I power it up, the light always starts in lowest mode. I can program what mode it starts it. Or I can program it to have mode memory. Or I can program it so that it will not power up. All without opening up the light.

Lots of options with this driver. :)

Technically a mechanical switch is not needed. There is a feature to avoid accidental activation on the E-switch "superlock" and such. Parasitic drain is not much. I prefer to have a mechanical switch though. Its also very handy when programming the light. If you mess up, just easily turn the power off and on.

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Shhhh!!! Do you all hear that?

It's the sound of a flashoholic achieving flashlight nirvana. A rare (and usually fleeting) experience for any kind of holic.

Congrats big guy. That sounds like a true and proper beast.

20

Yes! looks like a driver with good choices …
The switch supports the current well? It has low internal resistance?
Series switch is a serious design flaw in my opinion, it is almost impossible to move the flashlight in a bag or backpack with out accidentally turn on….
Always I have to move without batteries installed.