Review: ThruNite TN42 LED Searchlight

Hi Wolfdog, wow do you meant that some moisture got into the flashlight and it may cause this rare issue. I´ll try to dry the thing like you said. Then I will let you know. Thanks a lot!

No, No, No!!! I am sorry for confusing you.

Notice I said mine was a SEPARATE AND DIFFERENT ISSUE?!

Sooner or later someone will reply on here with a possible reason/solution.

Until then, REMOVE your batteries when you are not using the light!

I posted a picture of your light on the other thread which gets more traffic. The thread posted below that I mentioned to you.

Ahh!, haha thanks a lot for your effort and support. Now I understand.! :smiley:

Do all of the dies light up when the light is on? You would need a filter of some kind to be able to look directly at the LED when it’s very bright. I wonder if one of the dies somehow became a short. This would reduce the forward voltage of the LED (and cause that die to not light up) and possibly this caused the issue with glowing while off.

Look at the picture in post # 72! 3 of 4 are lit.

Hi Easy, I used two polarizer filter to look when the light is in moon mode and as far I can tell, all 4 dies lights ok. But I´ll try again.

Thanks a lot

Max

Yes these 3 dies remain glowing when the light is off. I looked again the led in moonlight mode and I can confirm that 4 dies are lights Ok. So strange…

Wolfdog,you misunderstood!! Easy asked to turn light on and see if the same [3 out of 4 dies on] thing happens?!! :person_facepalming:

I emailed HKJ….Hopefully some of the builders and modders on here will chime in. They may have an answer…my answers are unrelated to flashlights!!!

Well, I must wait for the knowledge and advice of some of the gurus in modding and electronics. Hope they can help me with this issue…

If all four dies are lighting at power on, I would suspect the e-switch wires maybe pinched or shaved and bleeding power to the emitter, not enough to fully light them when the light is off. There is always a bit of power going to the MCU via the e-switch, hence parasitic drain. There is a mess of wires between the inside of the head and reflector, they pass thru the shelf into the driver below, the ones I modded had sharp edges around this pass thru hole. I’m just guessing, but that is where I would look, first. Maybe remove the e-switch bezel and button and see if wiggling the wires kills the power going to the emitter, might even be the switch contacts on the back of the switch themselves? Then TN42 does have that lighted Blue ring when powered on.

Again just a guess, I haven’t had it happen to me…yet. but I am intrigued!!!

Hi Kawiboy, thanks for your answer. I´ll try to remove the e-switch bezel and see what happens.

Max

I do not know exactly how that light is designed, but a weak glow in the leds may not be a problem. Modern leds need very little current to glow.
I possible try measuring the tailcap current with the light off, then you can see if the drain is significant for battery life.

Hi HKJ, yes the flashlight seems to perform as should be. But the rare thing appeared suddenly yesterday! It means that something happens…

A couple pic’s to see what your up against!

I removed the e switch bezel with no results so far. A new thing noted is that this dim glow is not constant. I mean that if I look close to the light magnified on the reflector I see some kind of blinking.

Driver and Switch ribbon, very close to the ground. And a row of resistors!!!

You could remove the driver cover screws, pop the driver out and look at the switch ribbon for frays, maybe move it around a bit and re-assemble, and see if the emitter stops glowing? I wish I had it so I could monkey with it!!! :smiley: :+1:

I have some promissing news! I removed the bezel and pulled out a bit the wire ribbon of the e-switch and Voila! the glowing dissapeared to the naked eye. Then I push the flashlight agains my face to close all the surrounding light. It seems that the led still glows a bit but less than a GITD hand of a wrist watch.

I have to say that Kawi boy was right. it seems that the wires of the e-switch were causing the strange issue and I guess that the remainig almost undetectable glow that remains on the led (I repeat it only can bee seen in total darkness and a when the pupils dilate enought) is the famous parassitic drain. but correct me if I am wrong.

Thanks you all to help me to solve this annoying trouble and I hope it will serve to other that may experiment the same issue.

Again sorry for my english.

Woo Hoo Shorting! Well not woo hoo for you! But I seem to remember having something similar, but it was that blue ring power on thingy, it would come on when ever it wanted too? Never figured it out, so I ripped the guts out of it and put a 4S LD-2 M2 3amp Linear driver in it pushed that LED to the MAX and never looked back!!! :beer:

I dislike Boost drivers anyways, their sooo temper -mental!!! :smiley:

You can get ya some liquid rubber, I use Dynatex Brush On Electrical Tape and try to cover where ever you have that short, just let it dry completely or the vapors will fog your reflector if not dried fully!

Yeah found out the usual way, the hard way! :wink: