Airport Express opened up (the hard way) and fuse removed:
The faulty fuse itself, unwrapped (originally it was wrapped with yellow isolation tape - quite astonishing!)
The layout in detail; the fuse normally sits to the left of the blue and brown cables from the 220 V input; note the strange see through plastic wall to the left and and the bottom of it:
Everything in one picture now:
Again the layout, now from another side: