IBM 5155 Manual To Operations page 293

67
Align the slot of the option retaining bracket
with the threaded screw hole in the rear panel of
the system unit.
68
Insert the screw and tighten it clockwise with a
flat-blade screwdriver or 5.5-mm (7/32-in.)
open-ended wrench.
Not Properly
Aligned Aligned
Option Installation 4-65