Q8, PMS SEND TO THOSE WITH ISSUES BLF soda can light

Got it opened up and snapped a few photos. I’m not seeing anything that I think may be causing the issue. I’ve inspected all the closely spaced pins on the different components and I don’t see any obvious solder bridges. I’ll go ahead and give it a spray down with contact cleaner to see if that helps any. Beyond cleaning, what else should I do? Is there any testing that I should do with my DMM?





This was posted earlier here. Maybe it will give you a better understanding.

With enough experience I might learn to depend on it, but there are times where I wouldn't want to find out by experimenting. I'm not sure either way if it will be good enough, but this everything bumps only up and down argument sounds a bit oversimplified for representing reality too me. You may bicycle differently from me. Cruising around in the park is one thing. This is a commonly reported issue for cycling too. I wouldn't call it a flaw exactly, just not a strength.

Well, don’t take this too seriously (I don’t), but after pocket carrying it for 2 days, I’ve decided that the Q8 will not be my new EDC light.

My normal attire is cargo shorts and a polo shirt, and the left cargo pocket is usually dedicated to a tube light, either 18650 or 18350. If there’s a Q8 there, I don’t really enjoy biking (the Q8 has to go in the pannier), and the weight is quite noticeable. Shocking, right?

I’ll try just about anything in my EDC rotation, but after 2 days carrying the Q8, I’m looking forward to the return of my jaxman e2/convoy s2+ hybrid nichia 18350. Just in (the unlikely) case anybody else was wondering. :wink:

When my grenade pouch comes in, I might try it again.

You shouldn’t be carrying the Q8 around in a pocket, any fool can see that with the correct D ring installed it is meant to be a keyring light.

/\ … Yep…… :smiley:

ElginAgain double check for micro traces of solder between the pins of U2, on the side with U2 printed, it probably is just flux but you never know :slight_smile:

Cheers David

I can’t imagine the Q8 as a EDC light unless it was in a pack. Yup, I’d choose another. Great light just not a pocket light. But maybe on the bill of a baseball cap? (just kidding!)

Ah, good. Having the hardware should make it a lot easier to develop. I gave it a try briefly and ran into several bugs right away, so I figured I’d wait until it was a little more stable.

Is that easier than long-press-off?

Anyway, I’m still waiting for my Q8 to show up. Looking forward to another toy, particularly since it has extra features none of my other lights have. :slight_smile: (no idea when it’ll be here, but hopefully soon)

I use the Q8 as a riding light and have had not lost contact once with my mount. I only ride on rough trails at worst and have no issues hitting cracked spots, riding over branches, or going up/down curbs. It is true that most forces of hitting something stiff, or a hard drop will not cause the light to shut off because the forces are mostly perpendicular to the batteries. It isn’t very hard to understand. It would take something like rough mountain biking and a small tree causing the wheel to jolt in an uncontrolled manner to cause disconnect. Due to the weight of the light my mount would be insufficient to handle the sudden repeated forces of such riding. I don’t think the disconnect “issue” is real because riding that would cause it would break the mount trying to hold over half a kilogram of flashlight in place. If you are doing that kind of riding and take safety seriously you should be using a light on your helmet so you can quickly survey the uneven terrain. A handlebar mounted light would be ill-advised for that kind of terrain because the handlebars won’t always be pointed straight.

Yeah, it seems like if the light is pointing forward, only a hard blow of being hit in the rear by a vehicle could cause the batteries to compress the springs and shut the light off. IDK, I was just wondering. Pay no attention to me.

For biking I would UAW magnets on the - side of the cells just to be sure.

ElginAgain, good you gained access I hope people with knowledge chime in on the clear! pics.

B42, have some sanding paper ready, the black is easy to remove and the result is something most probably like better, a Natal colored ring around the switch goes very well with the bezel.
Really curious how those switch covers look.

Try this, akovia

It’s not a bug, it’s a feature.

Seems to be another batch of boards. I don’t have this “bai hai hong” printed on mine.
At first glance I can’t see any shorts either, but soldering looks mediocre. Next i would use the multimeter to check all components for shorts, continuity and resistor values, here is a circuit diagram . You could also measure current when light is off with multimeter and power supply, this might give a hint where the current flows. Wait a few seconds after shutting down before you check until the mcu goes to sleep. And with an oscilloscope you could check Pin 5 and 6 of the mcu whether there are any spikes.
If there aren’t any new findings I would re-solder all pads and see if it helps.

I’m in France. My Q8 left Sept 15th and arrived yesterday via the normal route at Roissy. No duty to pay. Packaging was trashed but the light seems fine.

The Q8 is a stupendous piece of work for $40. Between that, my MT103 and my old DEFT I am done for big lights - I’ll run out of trees to melt fairly soon otherwise. I haven’t touched anything on the UI yet as it seems just fine for now. Love the ramping, takes a minute or two to get used to and you’re done. Added my standard shoulder-strap to it and I suspect it will be my regular light for night-time animal duties for a long time. It will certainly be hard to better it. Just brilliant and well worth the wait.

Thank you to all involved, especially the Miller and Tom E. Can’t wait for the FW3A now…. :smiley:

Not sure if this was posted.

FLIR thermal photo after cca. 5min on turbo (stepdown disabled) with fresh 30Q and no mods.

Thank you BLF team !

any plan for white light ?

I’d take a careful look around R3, in case there is a dodgy joint or the resistor itself is faulty , though it seems to look OK.

This 100K resistor is there to drain the FET gate voltage to ground when the gate is not being actively driven by the MCU.

If it has become disconnected, this might explain the very slight current flowing through the LEDs when the MCU is asleep, depending on how MCU pin 6 is left during sleep.

E.g. if MCU pin is left floating tri-state (and R3 has become disconnected), only the tiniest leakage current would be enough to charge the FET gate just sufficiently to turn it on very slightly.

Check resistance measured at the FET gate pin to ground.

Should be no more than 100K (depending on whether much meter current flows through MCU pin as well). Try with meter probes both ways round, in case in one direction MCU pin protection circuit conducts. Generally black probe on ground should be OK.

Maybe afterwards try re-touching R3 solder joints anyway, if you feel up to it.

Well, that’s my hypothesis, for now, with a lot of “ifs” :wink:

Otherwise maybe a leaky 7135, but you would have to disconnect it to diagnose that.