Is that a fault of the switch or something else?
I think some drivers might just do that. My d4v2 (SST20 4000k, standard driver) has a bit of afterglow, which quickly fades and disappears. It’s only detectable in the darkest of rooms, and is undetectable after about 5 min. I think it would be more noticeable with the giant sbt90.2 emitter. @KawiBoy1428 does the glow fade, or stay on always?
Mine is definitely staying lit for hours. It’s like the lowest moonlight I have ever seen. It goes right off if you loosen the body from the head.
I turned off the heat control but I was afraid of frying everything …
On… it’s added parasitic drain… I tried testing it with my Fluke… it was fluctuating wildly on the uA setting around 590uA…on my UNI-T amp clamp I got .050 amps on the 2amp setting or 50 milliamperes draw…
Hhmm, the proto has the glowing LED and high parasitic drain too. The production unit I have though is OK. Hopefully today I'll do some research on it.
Update - Ok - weird but I'd say the proto doesn't have a leak now - measured about 800 uA but that could be because I'm using yellow switch LED's and they needed lower values resistors. Did check for glow, and the LED still glows at a very low level - gotta be in total darkness to notice it.
The glow, however, does mean there's a leak issue, maybe partial ground short, maybe a bad component. I'd normally suspect a 7135 but this driver uses TA's design of a resistor bank instead. I would first check the driver for cleanliness and clean it up if stains, flux, etc. and carefully check soldering.
Thanks for this info Tom, if mine is glowing and i notice it bothers me, i may PM you or TA for some additional advice for locating the "leak". Thanks again!
Hmm, that glow is a really strange issue, there are a few places it could be coming from but the driver design itself I know is ok so that just leaves either components or damage.
Possible that they got a bad FET that has some leakage I suppose although I speced out the FET’s for them to get and pretty sure they got the ones I speced. They are the same ones used in the GT4.
Another possibility is there is a very minor short inside the reflector to the ground wire, this was an issue with the prototype shorting to the reflector and why they had to move to 2 sets of wires. Anyone removed the reflector? Does it still glow with the reflector removed?
Dude, that looks like it will reach the moon. Great picture.
My WT90 led glows too when off, it goes away when I unscrew the tube. But it is so weak that I expect it to be 1 micro-amp or something, anything in the construction or driver can cause that. No worry at all in my case.
the reflector slightly shorting the ground wire would make sense, can anyone verify what TA asked above? I will check for this if mine is doing it when i get it.
That would actually worry me, but way more likely is a tiny leak under the led, between the led-minus pad and the center pad, perhaps the used flux is not a perfect insulator.
Yeah, some leftover flux makes more sense for a very slightly glowing LED.
Oh, well that'd be great if that was it. an easier fix for me than messing with the wires or a capacitor (?) or something else.
Just checked my WT90 and the LED glows very, very slightly. I removed the reflector and it still glows. I cleaned up as much as I could around the emitter (obviously can’t get under it without reflowing), and it still glows. Hoping someone wants to try reflowing their emitter cause I’d hate to desolder the emitter leads again for no reason…
@Tom E, what do you mean by resistor bank? I’m only familiar with the TA driver topology published here: https://budgetlightforum.com/t/-/41018
Some minor thoughts on the design and machining which are not complaints:
- It’s sharp, yet a bit slippery without any knurling. I know it’s unfinished and raw anodized, and I understood what I was getting into. Still, I found myself filing down some of the sharper corners and edges.
- I wish more flashlight makers indexed their body tube threads to align logos consistently. The Wildtrail name on mine is on the side and a little toward the back.
- Tactile rubber e-switch with press-fit rings like those offered by Emisar/Noctigon feel a bit more quality/satisfying than the WT90’s.
- The scalloped portion of the heat sink fins is very attractive. Art deco vibes.
- The middle pillar of the tail is shorter than the three legs. I think having it the same length would make tail standing more stable in most scenarios (maybe there’s some advantage of a shorter pillar for compliant surfaces?).
- I think the cell carrier should have some sort of emergency access hole at the top in case it gets jammed into the body. Imagine a bit of dirt getting into the gap.
Final update on the fake P42As: The seller told me their supplier “accidentally mixed in some sample cells with their order” 
. I’m keeping the cells (it is technically illegal to traffic counterfeit goods) and getting a refund. However, my MC3000 tells me that the cells’ discharge curves are spot-on compared to results from HKJ’s tests. Internal resistance is ~10 mOhm higher than nominal, but I’m not sure if it’s statistically significant. Bottom line is to stick to trusted battery vendors unless you’re willing to do deal with the potential trouble.
Without having to unsolder the emitter, you could unsolder the minus led-wire, it it glows after that, it is a leak under the led for certain, if it does not glow, it is something in the driver.
In either case I would do nothing, I do not see it as a defect or even as annoying if it takes years to drain the batteries (unlike my FT02, the parasitic drain empties the batteries in a week 
)
That’s a good debugging insight. Thanks for sharing!
Edit: wrote some stuff but deleted after I realized I misinterpreted what I read earlier
Sorry… it is a Defect and an Annoyance….it annoys me that I can not to recommend this light to my group of flashlight enthusiasts or anybody else because of the defect…. fix it and they will come…and buy…
Aweesome, thank you for the tip djozz