IBM ThinkPad T20 Hardware Maintenance Manual page 109

When installing: Make sure the followings:
a -parts of the insulation do not come off.
v
b -part ( b' s are only for T23 series) is not turned
v
over.
v Holes in the guide rail and in the aluminium sheet are
aligned, and the aluminium sheet does not protrude in
the c -parts. The protruding parts of the sheet can
cause electrical short.
c
a
a
ThinkPad T20, T21, T22 and T23 series
Removing and replacing a FRU
b'
b
a
b'
105