> Many thanks for the reply, Doug. I tried doing as you advise but no
> luck, I'm afraid.
If you're adamant that you want to open it up, and
assuming that your 3170 is close enough the same as
a 3200, then remove the top cover. (completely, lift the
posts out of their slots) You'll find a phillips head
screw in each slot.
Lift the rear *gently*; be extra careful with the corner
nearest the lock - the top and lock are entwined. Once
the rear is completely free and lifted an inch or two,
move the whole top towards the front of the case. Careful,
not too far, there are fragile wires connecting the switch
and top plate.
Good luck, and take care.