A few days after the vacation, daddy (me) finally finished copying all the photos from the digital camera to the big external hard drive. Left it lying in the living room, in the corner where all the tech stuff frequently lies. In come my boys, and I'm not sure why, they start plugging power supplies around. Unfortunately the one from the laptop fit into the hole on the external disk, but had a different (higher) voltage. Result: 1 fried hard drive, containing all the baby photos and videos of said boys up that time.
I still believe that it's only the circuit board that is fried, and the data is still all there. I still have the hope to find a used disk, replace the board and all will be back.