SupBeam K40 L2 Mod'ing - tear down

Flashlight Modding and DIY Parts
1

I started on the K40 L2 mod, did some stock measurements, played some, found the parts to be fully interchangeable with the TN31. The bezel came off easy, so could pull off the reflector and see the emitter/star. This is what I saw:

One screw there, the other MIA, just epoxy where the screw head should be. Closer:

Next, removed the driver and star. Wires are 24 gauge (could be better), copper star looks identical to the TN31's, and driver of course just like the TN31:

Some driver close-ups:

Star (PCMCB) close ups:

Now here is a close-up of what I'm thinking is a broken off screw:

I ended up using a small drill bit, and drilling out the piece. I tried needle-nose first to grab onto it, and unscrew it, but it didn't budge and was too low to get a good grip.

The main threaded connection just above the mag ring was super tight. Tried the BOA strap wrench's with no luck - I thought it was said these aren't glued. However, I've come across every possibility with the TN31's - some glued on this thread, some glued on the tail threads, some glued on the bezel threads, some not... So after no progress, tried the heat gun and that did the trick. Here's the weapons:

Here's pics of the parts. Notice the main threads have greenish color stuff - not sure if this is "green" LockTite or what. I've seen blues and reds, but don't think I've seen green before.

Notice the ball bearing - this sits on a spring. Must be careful not to loose this. I'm thinking of cleaning up their gunk and using Nyogel instead. It seemed to work well on the TN31's, but not sure if it will make it smoother.

Major components:

Everything:

2

Tom E, comparing TN31 and K40, what is their difference in dimension for their reflector?

3

Ohh - didn't measure, but the K40 is clearly shorter and narrower. I'll take the measurements and will post here, hopefully this eve.

4

Interesting. So on these big copper pills, does the LED actually sit on a bare copper patch or is the white coating under the emitter too?

5

Reflector sizes:

TN31 - outside width: 69.6mm, inside width: 65.2, depth: 65.4

K40 - outside width: 69.5mm, inside width: 62.2, depth: 52.0

6

Should be a bare copper path. On the TN31's, the center pad has continuity with the bottom of the star (direct thermal path), assume same here, but will verify when I remove the emitter to check and re-flow it.

7

Thanx for the close up shots especially for the driver, TomE.

This will help me in troubleshooting my K40 on its relatively low LED current even at direct drive. :slight_smile:

8

I should be a direct path, based on how the board design looks.

9

Thanks for the measurement.
TN31 has a ratio of more than 1, I means ratio of depth/diameter. That makes her the best thrower for 65mm diameter reflector flashlight.

10

From memory the greenish Locktite was for holding bearings or the like onto shafts. 601 rings a bell.

11

Looked it up on the LockTite site. They rate it's strength in between the blue (medium) and blue (high), but say it should be applied after assembly - weird... Info here: http://www.henkelna.com/us/content_data/168592_LT4985_Threadlocking_Guide.pdf

12

Is this thing (inside yellow circle) a resistor? If so what is its specs?

After thoroughly checking the driver of my K40, I found out that this thing is missing in mine. I guess this maybe the culprit for my K40’s relatively lower output. Can I put any resistor in there/

13

Here's a TN31 for comparison:

Notice the values of the large resistors is different. NightBird - not sure bout the missing resistor - it is odd though.

14

Yes the Thrunite’s sens resistors are 2 R082s, the Sup Beam’s are an R100 & an R082. I think the value of that resistor is 682? Its the way I see it in pic 5 of your OP.

I’m looking for a similar resistor and the closest I saw is spec’d 760 which is from a defective video card of an obsolete computer. I’ll be harvesting this, install it on my K40 and see the result. :bigsmile:

15

Installed the 760 resistor I ‘harvested’ from the defective videocard and there was no significant increase in lux. Removed the 760 and installed a 330 resistor, still no significant change in the lux readings. :slight_smile:

Perhaps a LED driver expert can chime in and help me solve this problem? :bigsmile:

The tailcap readings of my dedomed & direct-wired K40 is 3.77 Amps at 11.67 volts. My LED readings on the other hand is only 2.55 Amps. The ‘neck’ of my K40 easilly gets hot after shining on high for a few seconds. Its average lux reading is only 213 KCD. :nerd_face:

16

whats the circuitry in the tailcap for? guessing it must be reverse polarity or something of the sorts, but dunno

17

I have no idea what it does too. :~

But speaking of the tailcap circuitry, I haven’t looked into it yet. Maybe its the one affecting my K40’s output? Thanx Pulsar! :slight_smile:

18

After finding out that my BTU lux readings are higher (409 KCD vs 225 KCD) when taken at 11 meters in the office (as opposed to 6 meters at home), I went back home (which is only 4 kms from my office) took my big lights back with me and took its lux readings at 11 meters.

My K40 2081 lux (average of 5 readings) at 11 meters which is about 252 KCD. Relatively higher than the previous readings of 215 KCD but still far from the K40s modded by TomE & vinh. :~

19

they obviously didn’t tell us all secrets of their modds :stuck_out_tongue:

20

Umm, haven't mod'ed a K40 yet. Working on the one posted above, and finding the same thing, sort of. Did the jumpering of the resistors and read 3.1A at the battery carrier (9.3A effective??), but lumens and throw are low: 1,100's for lumens, 308 kcd for throw. This isn't much better than stock amperage and just de-doming the emitter!! So, maybe you do have to go the route of resistors, and not just jump them out, like what Ryan did here: https://budgetlightforum.com/t/-/20567.

No idea what vinh has done to the K40's. I know he and I jumper the resistors out on the TN31 and that seems to do the trick.

Edit: Actually just read on CPF vinh stated in a post he removes the resistors and jumpers the connection for both TN31's and K40's -- didn't work for me or you apparently... Hhmm...... Went back to stock setup and I read 1.45A at the carrier, so 4.35A effective - kind of makes sense.