BLF A6 FET+7135 Light Troubleshooting and Mod thread

DJ, send it to me and I’ll fix it for you. Even modify it further if you so desire.

(I can only do this occasionally people, if I were rich I’d offer to fix any that don’t meet your satisfaction, but rich I’m not)

BG just confirmed they will send me a replacement head. I told them there was no need for a entire new head since only the driver is bad, but they insisted.

There is also a small problem with the centering ring being too tall causing it to “turn” the LED when tightening the bezel, but a bit of sanding and a reflow minimized the issue. Meanwhile my A6 remains unused, I’m a bit disappointed since I waited so long and expected a lot from this light, really wanted to see the A6 FW in action.

I’ve been pretty busy lately but I wanted to post that I received another 5a and a bare 3d. I tried to lego the bare with two of my anos to no avail. I didn’t put a caliper to anything but used my knife as a depth guide and the bare tail cap is definitely deeper to the “shelf” that meets up with the tube compared to the others. The bare would have no doubt been a d.o.a. had it been anodized.

I would recommend people first ask for a tailcap and/or new tubes as the tube thread length on mine seem consistent. But not the tailcap depth.

Thanks for all your input thus far my friends!

I guess I’m missing something but it seems to me that it’s less effort to put a few solder blobs on the retaining ring or put a metal shim under the retaining ring to raise it enough to make contact. It’s only a $25 light and if fixing it takes less than 15 minutes then that’s the approach I would take.

I agree. Had mine come in doa -I personally would have. But at the same time I can’t blame people for wanting bg/manker to make it right. I think the idea being that if manker is going to do more business with us (cu/ss lights) they should at the very least test everything that leaves their shop. But in the end…… solder blob/paper clip is way less headache! :wink:

Is there room to add a second retaining ring over top of the first one, to make that contact?
Are the rings a standard size?

I think expecting perfection from a cheap item is unrealistic. Desirable but not usually reality :wink:

Heck I’ve bought many guns that I’ve had to tweak to make work right with the ammo I shoot. And they costed a wee bit more than most flashlights.

I like that idea! But on the tail the tube is really meant to touch the cap outside of the ring. I just looked at one of mine and you’d be lucky to get another ring threaded in but there is one thread showing.

How did you get the head off?

I finally modded my A6 with a triple and bypasses inside both springs. Output (and heat) is really stunning for such a small light.

I get a verry audible whine as well. The higher the current the louder it gets. Retouched all solder points on the board, and it’s also there without the springs and tailcap! Would drowning the whole board in epoxy help to get rid of the sound?

I understand that this is caused by rapidly switching between no current and 10+ Amps.

Summary of my issues.

Basically had problems with bad soldering on 7135 chip. Could not get the head open, maybe mine was glued, I don't know. Contacted banggood general customer service email on 23 September. Got reply on 24th, offered to send me driver only. Declined as I suck at soldering and I can't get the head open, insisted on full head instead. Agreed and head was sent out on 27th September. Today it cleared customs and on the way to me, should receive it sometime next week.

Pretty prompt response I would say... on another note, how do I open up the head?, pliers and elbow grease?, I'm assuming it unscrews at the groove right above the logo.

Is there anything visibly wrong with the driver of my malfunctioning BLF A6 light?

Both wires have dry dry solder joints.
This may not be the cause of your current problem, but it will not be reliable as is.

If you have problems with the low modes, the 7135 chip probably needs to be re-flowed.
(Try to see if the there is solder below the tab on the back of the chip.)

What are the symptoms of the malfunction?

Flashlight won’t turn on at first press of switch, nor second most of the times. When it does, non-click presses scroll through a weird set of modes, with no moonlight but two identical low modes, a mid, and two identical high modes (this is as far as I recall) and the light will eventuality turn off itself.

How to reflow the 7135 chip? Completely de-solder and remove it? I have very basic soldering skills, this is the most advanced stuff I have ever done, but I don’t get any reply from “support” :frowning:

Add some liquid flux at each pin and the tab. Then add a little bit of solder to each pin with a hot (750 F) soldering iron.
The flux will make the solder flow where it needs to go.
Do not spend more than 2-3 seconds per pin with the soldering iron. Do not heat it up so much that comes totally free, allow at least one pin to cool down so the chip stays in place.

OK, so, the switch is FRIED.
Maybe I killed it definitively, maybe it was defective beforehand. Any suggestions? Can I cannibalize another light’s switch?

It takes the small Omten switch, not difficult to replace but you have to find out what fried it or you’ll just fry the new one too.

I suppose my iron stayed too long and cooked it. It does not click anymore.

> stuck head

I got mine open by putting a drop of penetrating gun oil (“nano-lube”) and a drop of electronics cleaner/lube (Radio Shack spray can, just a tiny bit) into the groove, drawing it around the whole groove with a toothpick, then leaving the head standing on the bezel overnight. Just a drop. Anything that penetrates into the head will vaporize all over the inside of the reflector and emitter. Don’t overdo it.

At least for mine, I think there was just crap in the threads jamming them — because lots of muscle twisting the thing in a padded vise with padded pliers didn’t budget it at all. Solvent did loosen it up — after leaving it overnight. Then I cleaned it very carefully before putting it back together.

I sourced a switch of the same shape, but orange in color, from a Xeno E03. I hope it will endure the amps, but the E03 supported 14500 cells so I hope it will do the job.