Symptoms
Doesn’t turn on.
Measuring LED ± connections shows something related to battery voltage when turned on. Saw voltages between ~0.9V to ~1.5V.
Testing continuity between B+ or B- and output + or - yields a beep. Didn’t test resistance, don’t have my probe clips with me so hard to get a usable measurement.
Schematic would be useful…
One observation is that after desoldering the LED and removing the driver, I noticed the insulation of the red wire had moved upwards, being exposed by few millimeters towards the end it’s soldered on to the driver board. It’s plausible it could have moved when I manipulated the wire during desoldering and removing the driver from the head. Or it could have been like that all along, possibly touching/shorting against the inside of the head.
So something is clearly borked but I don’t know what.
Recycle as e-waste or anyone have any ideas? Things to check?
P.S. I moved the insulation of the red wire down before taking these pictures.
Interesting that you’re getting low voltage at the led. I’m not familiar with what that would be a symptom of but maybe someone else is.
I’d say check all solder connections closely (that resistor looks suspect). I doubt anything could desolder due to heat in an aaa light. Perhaps a drop caused a solder joint to crack.
Yeah, weird. Might mean the driver is alive but not boosting the voltage for whatever reason.
You mean the one labeled something27? Yeah, I looked at that but didn’t investigate further, figured it’s just soldered at a funny orientation.
I’ll do some further inspection tomorrow, at the moment the driver is installed and connected on the head. Wanted to test if the exposed wire was maybe placing the driver into some protection mode but there was no change. (Before reconnecting, I also slid a short piece of heatshrink over it as to be extra sure it’s not touching anything)
From the picture, I also think that the problem may be caused by the incorrect soldering of resistor R27 (0.27 Ohm). I think it is the red glue holding it in place and not soldered properly underneath. Scrape off the glue with needle-nosed tweezers or a knife and re-solder. If that’s not the case, you can re-solder the whole thing. For me, this solved the Klarus Mi6 problem, which was probably the result of the lead-free solder cracking from the heavy twisting. In these small flashlights, it is not the heat that cracks the solder joints, but the high pressure on the battery.
Busy day yesterday so didn’t get back to this until this evening.
I tried resoldering that resistor. At least I think it reflowed.
So far no change. Thank you for the suggestion.
I might try reflowing the whole board at some point in the near future.
I don’t have a proper hot plate so I’ve done my previous SMT LED reflow swaps on the electric stove. Crude but effective.
With this driver being even smaller and so many small components on it, I won’t do it yet. Ponder about it a little bit.
Or I might ask around if someone near me has the proper equipment.
Would be nice to get this thing working again. I have two C01S’s but two working is better than one.
