Videogame console/ Smartphone repair

I'm a 19 year old German with holiday work visa in Japan and I did repair two 3ds systems back home. I think repair technical devices is fun but I don't really know much about it. Does anyone know somebody who could teach me something about it around the area of Tokyo? Or even better does somebody know where I could get a part-time job where I can do things like that? (I'm not good at Japanese but fluent in Englisch)
I don't know if that's the right place to ask this question so if anyone knows another place where I could look for that, I'd be happy about you help too ^{^}