I was pretty amazed when after 1 year of use my headlight broke down experiencing cable problems on the side where the cable enters the light head. Didn't thought much about it and put it all on a bad production sample, just returned the product to the store and got a brand new one instead. I've got mine from a local supplier, Himalaya, having luck on my side as there guys are big and serious about their business with all interests in keeping a good name about the products they promote.
All was back and track again till 1 year after when this 2nd headlamp failed with same symptoms. This time I was more than intrigued and determined to get tot he bottom of it my own way.
There's nothing you can't do with the right tools so in no time it was all pieces on my worktable. As I was anticipating, the good design from the outside was found inside as well. The LED chip is mounted on a separate PCB that has an extra aluminum radiator for efficient heat dissipation. Even more, a thermal probe is mounted on the heat-sink for thermal shutdown protection.
The LED chip looks like a Cree product but I might be mistaken. All looked fine with the solder points so with a multimeter found my problem to be inside the cable. Only solution now was stripping it apart little by little.
Need I say my surprise when finding the inner conductors? I couldn't believe my eyes, finding the wires in such a bad shape in such a high overall quality product. It looks like the wires suffered severe aging problems from low temperature exposures, at least that's the only thing that makes sense to me. They isolation layer lost it's elastic properties and cracked all around in multiple places. One of them got more mechanical stress than the others and that's how the electrical link failed.
The only thing I could do in this case was to cut away the most exposed part of the cable and resolder it to the PCB. Of course it got shorter in the process, of course I didn't solve the problem, just the effect but for now it will have to do.
UPDATE: Another Petzl Myo XP repair