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Eyc headlight problem
On Sunday, March 28, 2021 at 6:08:50 p.m. UTC-4, Frank Krygowski wrote:
On 3/28/2021 1:01 PM, Jeff Liebermann wrote: On Sun, 28 Mar 2021 11:40:08 -0400, Frank Krygowski wrote: I tried the switch (and I do dislike "soft" switches buried under rubber covers), I felt the wiring connections, spun the wheel a few times, then it came back on. Rode ten feet and it blinked off. Then back on and stayed on, mostly, but would occasionally blink off then back on. At one stop to listen to a chorus of frogs, the Eyc was running only its standlight when it suddenly blinked off. That tells me it's not a wiring connection or an internal dyno problem. It must be a problem inside the headlamp itself. Also, it's not triggered by bumps AFAICT, and it sometimes blinked off while riding a perfectly smooth surface. Fortunately, it always came back to life and for the rest of the 15 mile ride it blinked out only occasionally, and for never more than a second. But its very worrisome. I've seen similar symptoms with LiIon flashlights and battery powered bicycle lighting. My guess(tm) is a loose connection somewhere in the wiring system. As you mention, it could also be inside the light. The erratic intermittent behavior suggests that it's NOT an electronics component failure, which would be more cyclic. Most commonly (in flashlights), I see this caused by the LED COB. The LED is soldered onto the PCB (printed circuit board) forming the COB (chip on board). The PCB will flex as the LED heats up eventually breaking the solder connection. The solder doesn't really melt, but instead cracks. I fix these using a hot air SMD soldering station: https://www.google.com/search?q=hot+air+smd+rework+station&tbm=isch Tear the light apart, and touch the LED or slightly bend the PCB while the lamp is operating. If it flickers, you found the problem. It can also be components other than the LED, which should be detectable by bending the PCB or visual inspection. Using the SMD soldering station takes practice. I suggest you find someone who knows how to use one. Another problem I've seen are crappy wire connections. These come in a variety of failures such as cold solder connection, bad crimp, insulation displacement, jacket creep, and corrosion. The best way to find these is by probing with a DVM (digital volt meter). The catch is that you can only find a bad connection if the light is in failure mode. If it seems to be working normally on the workbench, you're probably better off taking the light and wiring apart and pulling on each connection. If the connection moves, stretches, or falls apart, you found the problem. Corrosion should be obvious. Also, look for annual rings (usually black) around wires that run through holes in the PCB. Such rings are cold solder joints, caused by the assembler being in a hurry, and need to be restarted. I've only seen one broken wire on a bicycle, which took me weeks to isolate. I finally found it by pulling on each of the wire ends. One wire seemed to stretch, indicating a break somewhere. I found where the insulation necked down from the stretching and spliced the wire. Problem solved. This wire was NOT under tension and showed no sign of corrosion, so my guess(tm) is that the wire was defective from the vendor. However, my initial wild guess points to the Union bottle dynamo. I haven't seen any failures with these because I don't use them. However, if it's as old as you suggest, it might be a good place to start. Try powering the light with a battery or power supply. Then, disconnect one of the power wires. The B&M lights usually have a stand light feature, which is basically a supercap to power the LED while the generator is NOT turning. If you disconnect the power wire, and the light goes into stand light mode, and slowly fades away, then it's working normally. Therefore, the problem is likely NOT in the dynamo or wiring that power the light. I would need to be after the stand light circuitry inside the B&M light. Good luck. Drivel: https://phobia.wikia.org/wiki/Dizoangphobia https://phobia.wikia.org/wiki/Electrophobia https://phobia.wikia.org/wiki/BMWphobia https://phobia.wikia.org/wiki/Cyclophobia Thanks for the information. I've emailed Peter White and will say what he says before I dig in further. But as I said, I suspect the problem is internal to the headlamp because one of the time it shut down, I was stationary. The light was in standlight mode, during which it gets no external current supply. The standlight turned off just as suddenly as the main light was doing. But again, thanks. (I'm hoping that on the bench, powering this with a 6VDC battery should be as valid as powering it with a dynamo.) -- - Frank Krygowski Could it be that a faulty sensor is registering something as getting too hot and shutting down even if for a second or so? Cheers |
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