IF you fold back the steel enclosure you reveal the logic board attached to the hard drive by two small philips screws.

Thats it, your at the logic board. Reassembly is the reverse of these instructions.

A key point and lesson learnt for me here. When placing the enclosure back inside the white plastic case, start with the steel enclosure but leave off the black plastic retainer until the drive is nested in the white case with the connectivity ports realigned. If not and you try to place it back as it came out, the retainer will crease the steel.