Lenovo ThinkCentre 3231 Hardware Maintenance Manual page 117

8. To install the new hard disk drive into the blue bracket, flex the bracket and
align pin 1 , pin 2 , pin 3 , and pin 4 on the bracket with the holes in
the hard disk drive. Do not touch the circuit board 5 on the bottom of the
hard disk drive.
Figure 23. Installing the secondary hard disk drive into bracket
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Chapter 8. Replacing FRUs - Tower computers