On Wednesday, February 13, 2019 at 7:28:00 PM UTC-5, Steve Weeks wrote:
On Wednesday, February 13, 2019 at 3:49:50 PM UTC-6, Tanguy Ortolo wrote:
Well in fact, I will not need to try with another wheel. As I was riding
home, the noise kept increasing, and at some point, my front wheel
started to slow me with a drag similar to slightly pulling on the
brakes.

That's how my first dynohub failure presented itself. With the wheel off the ground, it wouldn't even spin a full revolution because of the friction in the bearings. If you look at the link I posted before, you will see a step-by-step account of the repair of a dynohub. It may be that the hub I repaired is similar enough to yours that you can figure it out. The "Joule I" hub and the Shimano hub may both be made by Sanyo, in which case some similarity is likely. The Joule I hub has two sealed cartridge bearings; the Shimano hub looks like it has one cartridge bearing on the output side and a cup-and-cone bearing on the non-output side.
You will need soldering equipment, but I doubt there is any aluminum wire to deal with.
If you are careful, you may be able to expose the solder joint by carefully prying the superficial parts off (see the link!). I initially did not do this, and broke the output wire and had to splice it (also described in the link).
Good luck!

Crikey! I sure wouldn't want a dynamo hub failure like that if I was riding far from home. I think that's another reason for me to stick to my external battery pack lights.

Cheers