.::Lain::. , those wall adaptors probably used some cheap 5V voltage regulator. So something like a 240Vac rectified to Vdc, then step-down directly to 5V.
Bad circuit! Wastes alot of power (wastes your electricity bill)! The wasted power becomes heat, lots of heat!
So this probably explains why your brother's wall adaptor got very hot.
I might just strip my wall adaptor to see what they use inside. But that'll be when i get back to aust, all my stuff is there.
Sorry for going off-topic..
