My idea for why some chargers won’t work was expressed in detail here:
I was hoping to get a response from a SanDisk person, but didn’t.
If the Clip charges ok when plugged into the computer’s USB port, but not with ANY dedicated charger, then I would think something is wrong with the Clip. Although frankly it’s hard to imagine what that defect would be.
If my Clip ever arrives from Amazon (made the mistake of using free shipping), I’m going to test it with a breadboarded circuit which will allow me to set the Data pins to various states, and then measure the actual charging current being drawn. Hopefully that will answer the question of whether the Data pins’ states matter, and if they do, which states work and which do not.
In any case, assuming that even the genuine SanDisk accessory chargers are dumb, then 5V is pretty much 5V, and it shouldn’t matter at all whether it’s a SanDisk charger or not. And if all the Clip draws is 140 ma, it’s hard to imagine a charger that wouldn’t easily produce that much without ripple or sag.
What’s strange is that we have such a variety of experience with these chargers. In several threads here, there are a number of people whose Clips charge on every charger they’ve tried. And yet in this one we have two whose Clips apparently won’t charge on any charger. It’s a mystery. In theory, I think, it shouldn’t matter whether it’s US or European.