BLF GT official support thread [FAQ updated 11 Jan 2018]

My GT arrived today. I am making a video of it performance on urban targets, such as the major league baseball stadium a few blocks from where I live.

Everything about my light is perfect. I read something a few months ago about the clicking sound in the glass from thermal expansion and contraction. I don’t remember if that is a potential problem, such as cracking the lens.

This light makes everyone in my house giggle.

OT: Out of curiosity, what can we expect from future LEDs? What could be the throw and lumen output of a BLF GT in 5 years?

I am sure things will continue to march forward, although it seems most development is towards larger high output LED’s and not so much thrower LED’s.

Just got my BLF-GT!!!
So excited… except for one thing: I only received 7 batteries!

Not sure who to talk to about this. The whole point was to get 8 matching batteries to use for this badboy!

Help?

Send Neal a PM about this.

Got my BLF-GT a few days ago. As we pretty much have have daylight all the time now in Sweden, i have not been able to test it outside yet. But I’ve tested it indoors and it worked great. A couple of times. Now not so much. I get as much light out of it as a key chain led light. I have tried the factory reset, and I can see that it ramps up from very low to only low in just about 1 second. All batteries are brand new and fully loaded. When i connect the batteries the GT flashes 2 times. What could be wrong?

This is really odd, I’ve never heard of this before.

What happens when you double click to turbo?

What battery voltage does it blink out on a triple click?

Double click gives the same as ramping up to max. Almost no light.
Triple click shows 4,3V.

Here is a smal video clip: Dropbox - IMG_2207.TRIM.MOV - Simplify your life (disregard from the cat noise :slight_smile: )

That is a very strange issue indeed. I would try removing the retaining clip on the driver and maybe pulling the driver out and making sure everything looks ok.

Then clean all the contact points really well and put it back together and see if the problem persists. If so then it looks like the driver is bad for some reason, it appears that the 2nd channel is not working for some reason. No idea why this would happen.

Yes to what TA said. The emitter, battery and switch all look good. It seems to be driver related. I typically mess around with the driver retaining ring on lights that have “an issue” and sometimes that fixes it.

In your video I think I see the slight blink indicating the top of the ramp even though it’s not at the 2A rate.

If this where a Q8 driver with a single 7135 and FET, I’d say the FET channel wasn’t working. This is a buck driver, though so I don’t know exactly how it’s channels are divided. So I will leave all that to TA.

The fact that it was working fine and now it does this, kind of makes me think something on the driver got fried or a component came loose.

Now I have removed the retaining ring and put it back several times. I have also looked for burnt components and bad soldering, but all seems fine, but the problem remains.

Here are some pictures of my driver:

My best guess is that a replacement driver will fix your problems. Have you ever replaced a driver before? You already know how to remove the driver, it’s just a matter of soldiering 5 wires to install a new one.

This is the cheaper fix for lumintop and the one I’m sure they would prefer. Otherwise they may have to ship out that entire middle section of the light which costs a lot more and probably takes longer to ship.

Let’s see what Neal or TA says.

I have not replaced a driver in a flashlight before, but I have quite good soldering skills, so I can’t see any problems (except for the short wires) doing it.

Now that I think about the pictures Neal posted a long time ago, the drivers already come with the switch soldered in place. Once you loosen the switch retaining ring, there are notches that allow the switch to slip through the hole quite easily.

So it’s really just the two emitter wires that need to be soldered.

Thanks!

It should not be any problems soldering it like this :slight_smile:

Edit: Fixed the URL for the picture.

Yeah. Let’s see what TA or Neal says.

I am guessing a new driver is the best option for you, there is a small possibility that the LED could be the issue but it is small.

Do you have a bench power supply by chance?

is it possible to buy a glass lens for my GT? mine is damaged

No bench power supply, but I have a lot of other power supplies. What voltage and amps do I need to test the led?

It was not the last I checked as it is very hard to ship them without them breaking. If you are in the US, there is a place that makes custom sized lenses for a reasonable price. I forgot the name though. Maybe someone else knows?