Novatac SPA SPL-120 Tail Light Mod

[pc_light]

Picked up a "user" SPL-120 with a damaged switch. After the switch repair I also performed a mod to add a SMD LED to serve as a "find me" light

The metal flex tab under the main switch was defective and required replacement, a relatively straightforward repair. However the pressure switch was also damaged and since I wasn't planning to mount this light, I decided to perform some surgery.

Trimmed pressure switch nub flush.

After much poking around and prodding with the multimeter, I discovered that there is enough current between the signal spring and battery to power-up chip/micro SMD LED.
After some cleanup of the pressure switch mounting pads I was able to mount a chip/micro SMD LED into the area. Shown here in series with a resistor (I had on hand) to lower current draw. I still need to tweak the resistor levels, to find the highest possible resistor to minimize current draw.

Here's the reassembled product SPL-120 tail light!

It's still a work in progress but I was pleased enough with the outcome to share. The tail light does not appear to impact any of the functions (i.e., Primary, Secondary, Simple Momentary & Minimum).

It's already "unlocked" for programmability. Next will probably be a reflow to something hi-CRI although the SEOUL emitter in there now is actually quite nice.

 

[datiLED]

Very cool! I like your thinking on this one. Hopefully it doesn't have too much drain on the battery with long term use.

 

[Jchang76]

Like the tail light! Very interesting look.

+1 for High cri or xpl-hi led swap!!!

Do the swap! You'll for sure for sure be happy with the results (a lot brighter than the seoul, wider hot spot, bright but modest enough to get good run time without a lot of heat at max or high levels)! And of course keep the NT driver. Still a winner in 2021/22.

Although that spl's likely red thread locked. On mine I had to go heat plus vise grips and i still knocked down flat a half inch groove of knurling tips, on two sides, even through a layer of rubber belting i had planned to protect the light's body with! I literally "ovalled" (just enough not to stay bent) the body with the vise grips to get enough grip. It was not a relaxing zen experience. Then there was the weird mcpcb shape that had to be made, and the funny prongs to solder to... and dont short the bottom of the reflector, but yes keep the focal length correct, depends on your pill type/ choosen mcpcb, on this one i had to belt sand some notches out of the back/ bottom of the reflector...

I know a lot of people have done this before me (updating NTs), not saying i have it all sorted out, not by a long shot.

But when finally done...so worth it! On this one i went sliced "dogfart lh351". Went from eeeeh-neat light, to heavy presence in the rotation.

Sorry if hijacking your thread! just trying to stress my highly recommending and wanting you to do the swap

Jc

 

[pc_light]

Very cool! I like your thinking on this one. Hopefully it doesn't have too much drain on the battery with long term use.

While awaiting some higher smd resistors, I decided to set the light aside to measure drain., in the 9-days since the mod voltage went from 3.80 to 3.72V. So the drain was less than theoretical but certainly higher than desirable. There's probably a fair amount of additional resistance introduced by the signal spring and various contacts points. Aiming for less than 0.1ma.

 

[pc_light]

Like the tail light! Very interesting look.

+1 for High cri or xpl-hi led swap!!!

I know a lot of people have done this before me (updating NTs), not saying i have it all sorted out, not by a long shot.

But when finally done...so worth it! On this one i went sliced "dogfart lh351". Went from eeeeh-neat light, to heavy presence in the rotation.

Sorry if hijacking your thread! just trying to stress my highly recommending and wanting you to do the swap

Jc

Thanks for the encouragement, a swap is definitely next. Here's a photo from 5 yrs ago when all I did was upgrade the emitter in my early gen EDC from the original Lux III to a Nichia 219C. Those EDS drivers were/are awesome. Back then "DA0GF4RTS6" weren't a thing yet but its a favorite now for me too.

This time around I'm leaning towards a Nichia 219B SW35K. I put one in an E2DL recently and couldn't get over how "incan-like" it was and I want to try that again. I was fortunate and opened my original EDC without incident. Here's my early gen EDC with the inside capsule. Actually that profile was par for the day when early Luxeon type "high-power" (ha) emitters were king.

Before, with OEM

After, with Nichia 219C

No worries about hijacking, any and all shared experiences are welcomed and keep 'em coming.

 

[Jchang76]

Nice. 219b Sw35 had got to be one of the nicest tint/cct around. At night around the apt and walking the dog I've got one in a aaa 47s bolt. Such a fun light that like the novatacs and i presume the old edcs, the pwm is acceptable.

When i need more punch at work during the day I'll go with the dogfarts and various cooler but high cri leds in the nts and other triples etc...

Id love to get ahold of the higher output hds lights and swap in some stuff. So far don't have the budget to add any hds new or used, nor have i been brave or dumb enough to mod my rotary. It's a high noon and I'm pretty happy with it but.... never say never!

 

[sween1911]

Beauty! My first serious mod was my old Novatac. Took me awhile to realize you used the weaponlight tailcap that already has the offset holes and repurposed the cord hole for a secondary LED. Very nice!

 

[pc_light]

Continuation of my tailcap light mod with the results - a hit, a miss and a hit.

I decided to increase the resistance to lower the stand-by current drain. I used a 1.5K Ohm resistor and the led continued to lit fine without impact to the mode changes. Along with trying several resistance level trials I also decided to swap to a green SMD LED instead of the red. On the basis of the observed current draw (143uA) I estimate the tailcap light and driver would drain a fully charged 800mAh battery in about 5 mos. Too high of a standby load for long-term storage but acceptable for the provided fulltime Moonlight mode and tailcap lockout indicator in a regularly used and recharged EDC.

Rather than to leave well enough alone (a modder's curse) I decided to take my mod to the next level with an emitter swap to a hi-CRI Nichia 219B SW35K. As others who have attempted HDS EDC mods can attest, that took considerable more effort. In order to reuse the existing pill, I had to reshape an MCPCB so it would fit, and modify the wiring connection to clear the metal reflector so as to maintain optimal focus.

Everything worked perfectly for all of a several second before then the dreaded "magic smoke" emanated from the light. I had overlooked a tiny renegade solder ball at the wire to MCPCB junction that must have shorted the Pos wire against the metal core. The driver would no longer functioned properly.


Since my original intent in acquiring the SPL-120 was to attempt a mod I had seen by someone using an FW3A driver in an HDS, that was how I decided to proceed. After some effort to remove the original driver from inside the epoxied SPA pill (argh). and then some more effort to salvage the original Positive/battery/spring contact plate I managed to create the replacement driver module, seen here (original FW3A driver (w Anduril FW) + oem spring plate)

The green tailcap light can actually serve as a moonlight mode with enough light to see close-up in the dark with adjusted eyes. So in addition to the Anduril electronic lock-out, if I choose to use mechanical twist lock-out the (un-lit) green tailcap light serves as an indicator that it's locked out. I could probably increase the resistor value to reduce battery draw but that would also eliminate the Moonlight feature.

The modded light is going to be my pocket carry for the next while to see how it performs, for now I'm liking it

-------
edited to update current draw observations.

 

[jon_slider]

Great tailcap and driver mod!

a few photos of Nichias in Novatacs

 

[pc_light]

Thanks Jon, frankly your HDS mods are inspirational. The Nichia 219B 3500K is , as you well know.

The tailcap mod was, as is often the case with mods, the result of trying to decide what to do about a damaged pressure switch. Simply plugging it seemed like a waste.

I would also have liked keeping the original 120P UI and excellent potted driver but again as fate would have it I got the opportunity to try the FW3 tailswitch driver mod. So now I have Anduril UI running in the Novatac instead.

Finally, I modded the signal from spring to brass bar so now I'm running it on 18350 battery as well. The light is seeing plenty of pocket EDC time.