[Solved] Flickering occur at high temperature.

Hikelite is right, the 7135 do have thermal protection but I've never seen a qlite hit it with an XM-L, only when running the MT-G2 with good cells. When you're running 3.04A into an XM-L2 there isn't much heat generated.

Even when you do hit it in my experience it is a gradual rampdown, not a flicker. You can see it happen pretty fast with the amp meter, but visually it doesn't look like a flicker to me at all.

Yeah I saw it as a rampdown also,not at 140C, but at 70C.

Has tried to run it direct drive with a single 18650 last night and the LED does’t flicker at all even it was very hot. So yeah, I can count out the LED already. Thanks RMM.

As you can see in the picture I have stacked four 7135 chips on it so it is running about 4.5A now. About the 140°C thing I think it’s very hard not to reach that temperature point because soldering process is already way beyond that.

Gosh, still cannot get rid of the flickering issue and have to check again tonight. That’s the thing I hate about adding chips. :frowning:

It's either a ground issue or bad driver. The question is whether or not it did it before adding chips, I guess you'll never know. I have had one non-functional qlite out of the hundreds I've installed now, but I have had two or three that moonlight didn't work on but all of the other modes worked great. Not quite sure what was different about those ones, but there definitely are some bad ones that slip through every once in a while.

Hmm, not sure if it is a ground issue as I connected a 18650 directly to the Qlite’s outer ring and spring without going through the pill at all and the LED flickers.

And I have changed into a new Qlite and did the stacking as before. The 7135 chip has 3 legs and each of them must not be connected with any other, is this correct? Because I’ve detected connectivity between the first leg and the ground leg, guess this is where the problem is.

I am done. I just cannot get this stubborn thing work.

I swapped with another driver and stacked four additional 7135 chips on it, assembled everything with the pill and tested with a 18650. It flickers like crazy even when it’s not hot.

Here are some pictures of the modded Qlite driver, please let me know if you find any problem with it.

And I didn’t do anything on the battery side at all.

I am definitely going to disappoint my friend who ask me to do this mod for him.

So you're saying it flickers with the new driver too?

See this post: Dead/flickering XM-L

Perhaps you can try to measure led conductivity in opposite direction (ESD diode)

Yes, and this time the flicker occurs in all modes even not in high temperature.

This is interesting. May I know what is an ESD diode?

Your case sounds similar with mine but two things are different:

  1. When I direct drive the LED with a 18650, no flicker or tint shift was noticed at all.
  2. My flicker occurs not only in moonlight or low mode, but in all modes.

And another additional information is this light doesn’t come flicker in stock form. Beside that I may have applied excessive heat to the LED during reflow. The LED was lit up like it is in moonlight mode +when my soldering iron touch the -ve or ve pad of it.

Any idea?

I have modded another 3 Nanjg drivers, stack 4 extra chips for each driver.

But only 1 out of 3 is working fine without flickering! Good thing is I am pretty sure it is the driver issue, not the LED or any other contact places in the body, but dammit what is wrong with my soldering skill?! I did the stacking in the exact way with three of them but another 2 are failure? I checked out Old Lumens chip-stacking video and seems like my working ways are exactly the same with his except that he uses a scissors-like clip to hold the chips in place.

Something is going on if you're experiencing flickering with 2 out of 3 of the same drivers. Are you bending the legs, possibly breaking them internally? How hot is your soldering iron?

Has anyone had his check the clicky spring and contact? Might be one of those 1A clickys as well…it gets hot and start drifting and loosing contact?

I had a cheap zoomie not too long ago, click it on…and could shake it and it would change modes, flicker

Opened up the end piece, the spring was weak and uncompressed and barely sitting on the contact for the switch, stretched the spring and made sure it had good contact…no more weak connection and flickering/mode changing

He does have a 3A driver with another 1.4A worth of chips on it, could be straining the connection inside the switch itself

Ah, someone has mentioned the switch…and he has changed it

Does it flash/blink if you put the leads from your multimeter on the battery - and ground to the body and hold there with solid connection while reading amps?

At 4.5A have you done the solder braid high current draw mod? What kind of battery are you using?

The LED lit up when you touched your soldering iron to it? Sounds like your iron is leaking AC and maybe damaging the circuitry.

Yes I did bend the legs of the 7135 chips for easier soldering, but isn’t this is exactly what you guys do too? At least Tom E and Old Lumens always bend the legs as I know.

I’m using a cheapo $2 soldering iron without any thermal adjustment at all, but I am pretty sure theiron was hot enough as when the tip touched the solder the solder melts immediately.

I am pretty sure that it wasn’t the flashlight body or the switch, because I tested the driver outside of the flashlight like this,

Yes, the LED did lit up when my iron touches on the Noctigon pad. And yes I am using a very cheap $2 soldering iron. So is it possible the the driver/ship was damaged by the AC current as you stated? Do you have any experience with this kind of issue?

I haven’t done any damage to a flashlight this way, but I killed a CB radio before by trying to add jumper wires to the PLL controller chip. A friend and I were trying to ‘hack’ the radio to get more channels, or channels that were out of the normal 40-channel assignment so you could have more ‘private’ conversations. It could have been static electricity or a random short but I remember I have had cheap soldering irons that gave you a tingling sensation when held by the metal part so most probably the insulation on the heating element had crumbled or degraded somehow. Needless to say, it’s very dangerous when this happens and you should just throw the iron away and buy a reputable one.

I see, thank you Piquelito. If the iron is the root of all sins then it’s pretty simple to me, just save up a bit and buy a good one. :slight_smile:

It’s really weird that I still fail many Nanjg drivers even I did it with a lot of care and patience. I hope more people will shed some lights on this soldering iron vs. driver damaged issue as this really sounds like it is exactly what bothers me for a long time.

Ouch. I ran through several cheap irons before. They are so poorly made. I’ve opened and seen AC wire strands all out of place - easily causing some leaks. Time to ditch that thing IMO. I mostly use hobbyking’s 3xAA modded to 2x14500 nowadays, they’re great. Wireless, very fast heat-up, and enough power for our modding use.

And secondly - bending 7135 leg is bad. You don’t want to stress ICs. Maybe some people got it to work, but noone can be sure if any damage is done internally. You could have caused micro fracture that gets worse with heat - that can cause intermittent problem just like your case.

My 2c.

Thank you Pulsar. So how much is your hobbyking’s soldering iron and can I buy them in local?

I am not saying that bending the legs have no harm, but seems like Tom E and Old Lumens do this all the time and have no problem. Perhaps I should try not to bend the legs when soldering them next time, but would that be another difficulty for me to bridge the gap between the top and bottom leg? :frowning: